If you have any old games with a corrupted memory unit (meaning it doesn't allow you to save your progress anymore) you might want to look at this.

These guys offer a relatively cheap service to replace your game's memory (10 bucks + shipping). They say they work on NES, SNES, N64, and Gameboy games. The actual memory you'd have to buy to replace it yourself costs 6 bucks + shipping so this doesn't seem like too bad of a deal, and you can save money by sending in more than one at a time.

http://www.retro-video-game-repair.com/products/1466-nintendo-game-battery-replacement-service/

Might be worth it for those of you with older consoles still kicking around.