The signature of Clockworkmod does in fact have "Idiot!" many times in the signature. It still does. I suggest instead of using huge fonts to shout at us here, that you shout at your brother. You are expected to be responsible for actions taken when logged into your account.
You might point out to your brother than his "prank" got you banned from a forum you were interested in, and it wasn't funny.
I have converted your ban to a partial ban - you can read posts and are not IP or email-address banned. I suggest making a new user (well, you already have) and try to keep your brother away from the keyboard.