If you have PC capable of TF2 but not played TF2 yet, this is your weekend. Free-play lasts from today through Sunday. Just one new map for tonight, Geoff worked on a push style CTF map so we'll give it a whirl. In addition if you haven't picked up arena_starship, it replaced cp_starship on rotation, you can snag it here.
ctf_research - looks alright, Ive got a few concerns about how it might play but we'll see.