1 - Tell you why I friended you. Assuming I can remember :)
2 - Associate you with something. A fandom, a song, a colour, a piece of fruit. SOMETHING.
3 - Tell you something I like about you.
4 - Tell you a memory I have of you.
5 - Associate you with a character/pairing.
6 - Ask something I've always wanted to know about you. (Or else I'll just ask a random question. I reserve that right.)
7 - Tell you my favorite user pic of yours.
8 - In return, you must spread this disease in your LJ.