Brawlhalla is pretty good, you can get it in Steam. It's kinda like Super Smash Bros. but 2d and different characters.
If you like VNs, Sepia Tears is a visual novel that plays with your tears. Not an eroge, but a vn like a storybook romance. Has some comedy. It's free in Steam.
http://store.steampowered.com/app/473770/ I've discovered it just today, and it's surprisingly very fun and also quite solid for being a free game! You should definitely try it if you're into futuristic race games such as Wipeout