How To Manipulate Internet Chess Ratings (works for lots of kinds of ratings where you can choose who to play):
When you're having a bad day, play your friend. Lose a ton of rating points. Now your friend is overrated. Have him refuse to play anyone. Next, play normally until you have some good days and your rating gets back to normal. Your friend is still overrated though. Play him and split up the extra points.
BTW if you want to play chess online for free, go to FICS. I mostly play on USCL.