I've started on, and often finished, a ton of projects for various platforms over the years. Here's a collection of those of them that I've been able to dig up.

Cocoa Touch
(iPhone applications)

Quat

Quat
A “Connect Four”-style game, written for the App Design Challenge run by the organizers of Apple's Cocoa Camp 2008. Lots of UIView's animation extensions, some Core Animation, and a bit of Cocoa's archiving mechanisms.

Mines

Mines
Classic “Minesweeper”. This was my third project for the iPhone, back in the 1.0.x jailbreak era, and was where I really cut my teeth on UIKit and the iPhone in general. A bit more than a year later (November 2008), I finally got around to updating it, bringing it to the SDK, adding neat things like Core Animation, and making it available on the App Store.

Tris

Tris
An unabashed “Tetris”® clone and my biggest success to date. Originally developed during the 1.1.x jailbreak days — I was disappointed by the existing tetromino games, which typically had horrible controls and slapdash graphics, so I made my own. It was the first app I brought to the SDK and the App Store, and was wildly popular (the #1 free app on the Store, with over a million downloads — plus the original million-plus to jailbroken phones) for the week-and-a-half before The Tetris® Company sent me a cease-and-desist. Plenty more information about that here.

Pong

Pong
My second iPhone project; I was investigating UIKit's multitouch capabilities and wrote a basic two-player pong game therewith. Notable for its aesthetic; I wanted to stay true to the stark style of the original game, but update it to make use of the rich color and detail of the iPhone's screen.

Photoshop
(Projects for “Principles of Visual Design” class)

Energy Drink

Energy Drink
The assignment here was to create an image from photographic reference in an expressionist style. I had a can of Vault lying in my fridge, so I went with that, trying to show the “energy” radiating from the can. I like how the splatters and sunbeams and such on the desk worked out, but the logo on the can — specifically the colors around it — could've used some more work… still, it's probably one of my favorite products of the class.

Absolut Poe

Absolut Poe
“Create an advertisement based on an existing one.” I tossed around a few ideas for this, eventually focusing on Absolut's famous ad campaign.

Garry's Mod

Demon Melons

Demon Melons
Started as an effects project — imitating the “corruption” in Ubisoft's Prince of Persia — this has evolved into an experiment in classical madcap sandbox gameplay. The watermelons (based on a common generic prop in Half-Life 2) hop around idly and chase players, trailing smoke and “tribal”-style sigils; when shot, they break into chunks as an ordinary watermelon would, but these chunks, unless destroyed further, quickly regenerate into entire melons. A work-in-progress; video is available here.

Omnivora

Omnivora
My entry in one round — “Gardening” — of the GMod Gamemode Coding Contest. Omnivora was a resource-competition-oriented pseudo-RTS; the objective was to grow and spread the player's plants while competing with other players for “food” — randomly-spawning NPCs that the plants could eat. The gamemode was a little flat and repetitive, but it ended up winning “Best Effects”, which was about what I'd expected.

Wormholes

Wormholes
Two objects, a black hole and a white hole; the first sucked objects in, and the second, when connected to the first, spat them out again. Notable for its visual effects — objects entering a black hole dissolved into black dust as they were sucked in (after which a refractive ripple emerged from the hole), while objects exiting a white hole glowed white and trailed sparks as they were pushed away. There's a video of this available here.

Advanced Turret

Advanced Turret
An extension of GMod's built-in “Turret” tool, adding a variety of firing modes and featuring a modular system for easy extension. The base modes included rockets, plasma, grenades, and flame, each with a completely custom-designed particle effect.

Handheld Portal Device

Handheld Portal Device
A recreation of the eponymous Gun from Portal. Evolved from a fairly amateurish one-shot coding project to an elaborate and detailed modification, encompassing modeling and level design as well as an enormous amount of code. The final version has seen more than <number> downloads and is still available here, though to my knowledge the recent updates to GMod itself have broken it completely.

Crate Maker

Crate Maker
A tool that enclosed objects in “crates” (boxes of various description), which when broken freed their contents — without regard to object size or composition, so a thirty-foot cargo container or snarling zombie could emerge from externally identical boxes. My second GMod project, and the first I released.

Cocoa
(Mac desktop applications)

Front Row Remote

Front Row Remote
A touchscreen controller for Apple's Front Row, designed for use with car computers. Normally invisible; a tap on the screen revealed controls similar to those on the actual Apple remote, which sent AppleScript-ed key commands to the Front Row application.

Aperture

Aperture
Inspired by the E3 2006 trailer for Valve Software's Portal, this was a proof-of-concept game engine I wrote for a high-school Calculus project. It was my first 3D engine and my first real use of OpenGL, and turned out surprisingly well nonetheless.

Victoria

Victoria
An unfinished “media center”-style application, developed likewise for use with a friend's car computer and notable for its use of the Mac OS's speech recognition engine to control iTunes. The user could make ordinary playback-control commands, or instruct it to play a particular song in the current playlist.

Mandel

Mandel
A Mandelbrot fractal generator. Multithreaded rendering, interactive zoom; one of my first Objective-C projects. The rendering code was pretty much directly ported from a BASIC program I wrote on a TI-81 graphing calculator… alas, I do not have a screenshot of that.

Unreal Tournament 2004
(Game modifications)

Drones

Drones
Small floating companion robots, inspired loosely by some Star Wars® concept art. Followed players, orbiting them, shooting yellow “plasma” at other players, and healing their owners as needed. Added some complexity to gameplay: killing a player with a drone protecting them was markedly more difficult, and even more so when the player had picked up more drones from defeated enemies.

ONS-Check

ONS-Check
An “Onslaught” map, one of the few memorable levels I produced for UT2004. It was set on a large, hilly wooden chessboard, dotted with huge chess pieces (my own models), and bordered by rocky cliffs. I playtested this with friends for weapon balance, exploits, and so on; the consensus from them and the Atari community was that it was cramped but otherwise well-made.

Deflector Combo

Deflector Combo
A custom “adrenaline combo” — a special ability players could activate — that deflected projectiles (as opposed to instant-hit weapons) away from the player, forcing the enemy to shift their strategy and weapon choices. The most challenging part of this was the network code - getting things like rockets (which in vanilla UT2004 had their paths mostly predicted on the client) to curve awaay on both server and client, that kind of thing.

Monster Mine Layer

Monster Mine Layer
Modified version of the Mine Layer. The original weapon placed “spider mines”, small robots that chased players and then exploded; mine was similar, but instead of explosions the mines produced small flying alien creatures. This was a lot of fun — it transformed a relatively unfair “oh, there are mines chasing me; I'm going to die” scenario into an interlude of frantic monster-fighting.

Swarm Gun

Swarm Gun
A modded Link Gun, built off ideas from some earlier projects not listed here. Fired a number of small green projectiles, which bounced off walls and chased any nearby players, including their owner. This was an effort to make the weapon more balanced in combination with the game's other guns — blind spamming without a target could quickly prove fatal — but was mostly unsuccessful.

Nix Gun

Nix Gun
An overpowered but highly enjoyable custom weapon, and my first scripting project for Unreal. Primary fire launched huge but easily-destroyed missiles; secondary fire produced a large, glowing ball that would slowly chase the player under the weapon's crosshair until it hit them or a wall. As the only weapon available (via an “Arena” mutator), made for pitched battles and players running in desperate evasive circles chased by huge glowing blobs.

3D
(Cinema4D, Maxwell, 3ds max, and POV-Ray)

Barkeep

Barkeep
One of my favorite Maxwell renders: a futuristic bar, and its friendly aluminum server.

Helicam

Helicam
My entry in C4D Café's Modeling Challenge. The task was to model a webcam; I made a small flying webcam with some HyperNURBs magic, rendered it with radiosity (which took forever, as radiosity is wont to do), and won the contest.

Menorah

Menorah
An entry for CGSphere, a gallery of CGI spherical objects composed following their scene template. This is a Hanukkah menorah, composed of a couple of cylindrical sections attached at interesting angles.