Java4k.com is cool. 60+ games, all under 4k. Sure, they wouldn't play on my Commodore Vic-20, circa 1984, but don't hold that against them.
Programming with such strict restraints is a fascinating, and entertaining, exercise. Each designer needs to focus on what is essential to the game's appeal, disregarding all else. Simple can be extraordinarily fun, as anyone who's played with a ball can attest.