Plants vs. Zombies. Totally worth the 10 bucks it costs. It's kind of a tower defense game, made by PopCap. I'd suggest you try the demo first, though, but considering the overall extremely positive reviews it has gotten... Well, it wouldn't be money wasted.
To sum up what the game's about: You are a human inside a house, who we never get to see. For some obscure reason, a gagillion zombies have decided to come and try to eat your brains. To defend yourself, you have to plant a wide variety of plants, which act pretty much like defensive towers, all of them having their own function. The game is quite humorous and lighthearted, despite the zombies, so you're in for a fun time. There's also a ton of different zombies with different abilities, so you'll often have to adapt your strategy.
Also, Zeno Clash. It's a pretty weird game, but the brutality and in-your-face feeling of the fistfighting is unparalleled, if you ask me. You'd want to try the demo, what with the game being a love-or-hate game, but personally, i've enjoyed it. Once again, try the demo, see if you like.
Gaem sum-up: You are Ghat, some tribal-dude in a totally bizarre world called Zenozoik. You happen to have killed your father and mother, which is conveniently one single hermaphrodite. Your brothers and sisters hate the fuck out of you, and want to beat you to death. In return, you beat the living daylights out of them. You also get to beat the shit out of some insane forest-dwelling humanoids called Corwids. To do this, you have a variety of more or less brutal moves, including, but not limited to: a strong punch to the face, several knees to the face, and a brutal sidekick to their chin, which sends them flying. There's also several weapons available, but the main focus is on fist-fighting.
Oh yeah, it's all in first person perspective, except the cutscenes.
Both games are found on Steam. =P