Probably osu!, this free rhythm game. When I used Xfire for game time tracking (and before it was shut down), I had clocked about 2000 hours for the game. Now, I'd be surprised if it wasn't above 5000 hours. It's just so easy to waste relatively short times on osu! every now and then! And no, I'm not a fan of rhythm games. I was reluctant to try the game but someone heavily recommended it, and here we are...







