Put this stuff in your mIRC remotes (Alt+R to bring them up) to make the channels not annoying:

on ^*:JOIN:#sda-charity-marathon,#sda-marathon-commentary: { /halt }
on ^*:PART:#sda-charity-marathon,#sda-marathon-commentary: { /halt }
on ^*:VOICE:#sda-charity-marathon,#sda-marathon-commentary: { /halt }
on ^*:QUIT: if (ustream isin $server && $me ison #sda-charity-marathon) { /halt }
on ^*:NICK: if (ustream isin $server && $me ison #sda-charity-marathon) { /halt }