Actually Nerull, Roms are perfectly legal, so long as you already own the game in question. Say for instance you have Zelda and the save battery died ages ago. You would be permitted to download a Rom of the game and keep it. Anything you don't own MUST be deleted in 24 hours. (That's what most sites say, but I'll go with the assumption that you shouldn't possess them in the first place. "Them" being games you don't own.)

Coolest game period on the N64 is in my opinion "Super Smash Brothers". That game just owns! I needed to babysit every once in a while across the street, and they had a N64 with games like Pokemon Stadium (we only played the minigames), Mario Kart (Multiplayer!!) and Super Smash Brothers. We just played endlessly, until we were so freaking good at it. One match lasted for like 30 minutes because we wouldn't die, and evade the other's attacks. Too cool :D