Quake 1
Rock Dodger (great homebrew!!!)
M.U.L.E. (GREAT c64 game, run it on frodo)
Narcissu (its a visual novel, get the translation and text patch (pm me if you need help) and run through onscripter)
Reminiscence (flashback!!!)
snes9x (super nintendo emulator, try out rpg's like chrono trigger and final fantasy 6/3)
neocdgp2x (neogeo cd emulator! Try out metal slug, pulstar, etc.)
nesgp2x (nes emulator, try out mario and zelda)