Print them out and play them hard.
As reported on Slashdot.org, Tim Schuerewegen has figured out the code system used in Nintendo's e-Reader cards. By cracking the Reed Solomon error correction he has enabled homebrew game makers to print out their games in e-Reader dot codes. The codes, which much be printed out via a special program, can then be swiped into an e-Reader and played on a Game Boy Advance.
There is a homebrew clone of the classic Game & Watch game Bombsweeper available for download. There are also a few other programs and documentation on the site.