If there aren't enough games to your liking on the Nintendo DS Lite, and you'd rather have some retro Famicom pleasure instead, you really need Cyber Gadget's Cyber Familator Lite. Plug the Familator into the DS' GBA slot, add a Famicom cartridge, and you can play all the addictive 8-bit games you want.
Importer NCS suggests plugging the whole thing into your TV and rocking the big-screen classic gaming, which sounds like a damned good idea to me.
Priced at $68, they're apparently getting "limited" stock this week.
Cyber Familator Lite [NCS]