Android users looking for something to fill the hole that Flappy Birds once occupied now have a less trivial time sink in the form of QuizUp. As you'd expect from a trivia app worth its salt, it comes loaded with tons of topics (over 400) to choose from, including lifestyle, TV and literature. And, since it's a social game, you can test your expertise in any of those subjects against friends and strangers. If the name QuizUp sounds familiar, it's because the app was released for iOS four months ago and became its creators' first smash hit -- it did for Icelandic studio Plain Vanilla what Angry Birds did for Rovio and Draw Something for Omgpop.QuizUp has already been downloaded over 10 million times on iOS, but (while it's still getting 50,000 downloads a day) Recode says the number of new users has declined in the past month. Plain Vanilla CEO Thor Fridriksson believes, however, that an Android launch will reignite interest in the game. We've yet to see how the Android app will affect the iOS version, but it isn't doing too shabby thus far: it's been installed more than 10,000 times since it became available. So, don't be surprised if a friend would rather hole up this weekend rather than go out and play actual bar trivia.