Riddler: A Free Collection of Puzzles and Riddles

Riddler is a collection of over 100 hand-picked riddles available free for Windows Phone 7. This app saves riddles you’ve already solved, and offers hints and solutions for every riddle if you get stuck. It’s a great way to test your wits, updated with new puzzles and riddles all the time.

Check it out for free in the Marketplace: Riddler