NFG has posted about 40 ringtones based on videogame themes, in MP3 form. They all loop properly and everything! A number of them, like the intros or stage finishes, are more appropriate for texts or notifications. If I used ringtones ever, I would certainly use these, but unfortunately I find any ringtone of any kind to be utterly obnoxious, and have my phone set to vibrate. Still, I’d rather hear Yuri’s Art of Fighting stage than Snap and Roll. Although I have to admit I kind of like Snap and Roll.
Update: NFG and Deusjester, among others, have put up some game-related phone wallpapers as well. Check the forums for that. Be warned that NFG’s links are not necessarily work-safe!