RetroArch is one of the most popular emulation ... Dolphin is far and away the best Gamecube emulator (and it runs Wii games, too.) It's also one of the few options for Gamecube emulation ...
[mac2612] has developed a custom retroarch-based firmware for the Leapster GS and LeapPad2. (via Bringus Studios on YouTube) We covered Linux on the Leapster before, but Retroleap seems better ...