Yeah, a friend of mine gave me DOTA 2, too. Once again, though, I just do not like MMORPGs. Dota 2 is supposedly like WoW. Do not want. And you should definitely check out Arma 3. It's only in its Alpha stage at the moment, but goddamn is it good.
Basically, if you have played Arma 2, imagine Arma 2 with much better graphics, a more stable engine, a better menu and inventory and pretty much all the bad stuff taken out of it, but more importantly, the good stuff still there (if it has not been improved). I really, really recommend Arma 3. Get it now, while it's an Alpha version and it's still cheap.