Ah yes, creepy people. My favorite ones are the stalkers you get from lurkers on gaf whenever you post your GT in a roundup thread. I don't add randoms anymore, but I remember this one guy had a habit of sending invites to play Uno, maybe the guy just wanted someone to play Uno with, or maybe he wanted to mash his hairy asshole onto his camera and into my life. Who knows.
Another creepy thing - When you ask these people if you know them, then you get an ultra creepy and cryptic response like, "I just got an xbox 360 and I'm just a gamer looking to connect with other gamers, maybe get some games goin, what are your favorite 360 games?"