I got banned from a room on msn chat years ago for a few days (twice in fact). I forgot what I did now, but the the owner came back and banned me again for no reason.
I got banned from using a trackmania server host for not obeying their code of conduct (that they somehow expected me to be able to read when it was in french:nuts
Had two accounts and got found out and banned. I've now registered again with a different e-mail and ip, and just have one account now.
I'm permanently banned from one irc server (me and the owner had a disagreement *him being an idiot over something basically* )
Haven't been banned from here yet though, and don't intend to either, as I wouldn't want to lose my site (put far too much work into it for that to happen).