Yeah, you get it automatically in your TF2 backpack for having the most mini-game duel wins in Team Fortress 2 out of the entire world population that played Team Fortress 2 on / for that particular 24 hour day. You only get to keep this "all-class" hat for 24 hours, then it "vanishes" out of your backpack. It's a temporary "reward" to enjoy for a (24 hour) day.

is that a rare hat? just asking?

thats totally not gonna be easy to get a headshot on