It's happened countless times to many people (including myself) So I just want to make it clear.
If weapons don't do any damage in a minigame even if you set weapon damage to "on", then most likely you have the Left 4 Block mod. What your going to have to do is go to the L4B section of your minigame window, and then you should see a check box marked "Team killing". Uncheck that, and you're good to go!
