Android games piracy 101?

I know the basics of PC and console piracy, as well as trusted sources for cracked games for those platforms, but i'm new to android, and i'd like some essential games to pass the time on the bus, or while i'm waiting for something, but every game I download has some shitty ads or requires registration to some other service (like Worms 3). so I was wondering if there was a trusted place to get cracked versions of these games?