Every server, despite the server variables set up, should be running the party mode all day today. Balloons, party hats, and gifts await all comers. If you're feeling a bit nostalgic, Team Fortress Classic servers should also have their own party mode up and running!
This mode will only be on by default for one day only. Everybody should join in on the fun and non-owners can get a small taste of the festivities as well before their free weekend time expires.