Every ringtone on my phone is from a videogame. I have the most memorable/interesting tunes from all Final Fantasies, all Zeldas, and a bunch of other games.
I have to have a shitload of them because each contact has their own ringtone and they are designed to fit each person. For example, when my office calls, it plays the fight song from FF2. http://www.youtube.com/watch?v=h2irrrY6as8&feature=PlayList&p=8891E34EB16950D1&playnext=1&playnext_from=PL&index=2 The standard one that plays when the number is not stored is the song for the crazy laboratory from the newer Zeldas http://www.youtube.com/watch?v=MnqTlNSP88o.
My favorite one I luckily don't get to hear too much. Its the one that is given to everyone whose number I have stored in my phone for the sole purpose of knowing when NOT to answer it. Its "dancing calbobrena" http://www.youtube.com/watch?v=zFTZuIcOew4&feature=PlayList&p=E5FD052F547A2816&playnext=1&playnext_from=PL&index=19. /cookie to anyone who guesses why I have it set to those people.