If someone is being a jerk, here's how to ignore them.
/ignore jerkhead12 +
Here's how to un-ignore them.
/ignore jerkhead12 -
To help other users in the room, it'd be nice if you posted a message telling everyone to ignore them and how to do it.
Let's ignore jerkhead! Everybody do /ignore jerkhead12 +
If the jerk continues to be an irritant, notify a channel operator, or ask an ircop for help.