X-Chat:
http://www.silverex.org/download/
As for mIRC, you don't have to pay for it, you just have to click the option to not pay every time you start it up.
You could always start up putty and use irssi 8).
As for starting the #firstrobotics channel up again, you may not be able to get the operators to hand over control to someone who would be more active. Starting up a new channel would be a better idea if you can't contact them.