I'm sure someone else might have a channel, but I just set up #mopedarmy on irc.freenode.net.
Point your IRC client (MIRC on Windows; iChat, Xchat etc on Mac) at irc.freenode.net and /join #mopedarmy
Let's get our chat on!
(This was inspired by the "what's your IM username" thread. IRC is so much more fun, like Yahoo chat but without so many idiots.