You like Team Fortress, we like Team Fortress, let's play some Team Fortress together! Developers from things such as Minecraft, Skyrim, and Team Fortress, unite with community personalities in a mix up match up battle for charity supporting Child's Play. There's a number of free slots available to be won. If you're interested in joining the match, stop by the
TF2 Mixup site and donate! All the specifics are available on the
Mixup Match 4 site.