Held in April 2013, the inaugural event lasted 36 hours and raised over $35,000. Players from around the world participated in the livestream and helped to make it one of the biggest events in Team Fortress 2 history, with more than 65,000 people tuning in.
This year, Tip of the Hats aims to set the bar even higher.
It's this weekend, the 29th and 30th (proper timetable on the official site), with lots of prizes, highlander, 6v6 and ultiduo matches, surfing, randomizer and all sorts of fun-looking stuff. There's a donate button on the official site (stream link).