Microsoft has just rolled out a new testing app for Xbox Live in the US called "Xbox Live Labs." The downloadable app, available through March 27, consists of a series of network tests, during which you won't be able to run games or movies.
What do you get for your time, besides a potentially improved online service? Each completed test will award a unique zero-point Achievement and an item of Avatar clothing, including a lab coat, brain helmet, or mad scientist hair, even though this science seems pretty mellow.
You can find Xbox Live Labs in the community channel.