IVDICIA: A study in minimalism.
Rayguns & Rocketships: Space opera straight from the comic strips & movie serials.
AL: A simple percentile system with skill-bundles.
Realms of Magic: Inspired by a board game.
Ars Heroica: Deconstructing the grand old game. (Plus some reconstructing.)
H&H: Roleplaying in the classic style.