We do have one thread going on over here
for general Android apps and gaming talk. It is about a year old so some of the recommendations in the early stuff may be a bit outdated (or not, who knows), but it's worth perusing.
My quick game recommendation is to check out Game Dev Story, which I love. And of course there are the "standard" games, like Angry Birds and Fruit Ninja.
I also highly recommend getting the Amazon App store, since they have a free paid app every day, and often times it is games or other cool things.