I've filed this under "funny", but really, I wish I could have given some of these rules to people I've known in the past. The Guidelines for Platonic Friendship has a lot of decent points that can save a lot of confusion for poor guys (and potentially girls as well). IE:
2. No sleepovers. I think of all women who sleep in bed with me as potential sex partners. I spend all my free time trying to coax women in, so if you get in there, I can’t help but think you want some. If you or I need a place to crash sometime, then we should employ a couch. The breaking of this rule is punishable by instant sex.
Hit the site for 15 more gems.