Somebody's writing a clean-room implementation of Solomon's Key for the NES. All of the original levels are already implemented. Theoretically cross-platform. Doesn't quite work yet but it's getting there. Includes a level editor so you can build your own levels. Seems to have some tricks to getting it to run but I haven't tried them yet.
Actively maintained open-source game remakes.
Classic video game sprites of all kinds can be found here. They make great icons.
linux games store purchase download support videogames
Everyone's favorite t-shirts from the 80's.
Free downloads of older shareware and abandonware games, applications, and utilities.
Someone fed ROM dumps from a couple of Atari games into distellamap and generated maps of function calls, with sprite dumps. Amazing, how simple games were back then...
An open source clone of the game Worms in which you manipulate a team of characters (usually earthworms) to box, pummel, blow up, and otherwise mangle the characters of the other team in a cartoon-like fashion. Network/deathmatch play possible.
An open source platform/strategy game reminiscent of Worms.
The website for a classic space trading/warfare game called Elite run by one of the original authors. Includes a lot of information and even the novella which was published with the original version.
Somebody cloned Portal into an open source game done entirely in ASCII. Cute.
Speedruns are when an experienced gamer tries to sprint through a video game as fast as possible without dying. The goal is rarely to avoid damage (in fact, strategic damage is often necessary) but to successfully complete the game in one go. Some are extremely short (a few minutes) while others are a significant fraction of the usual playing time