mfb

Here are some threads with examples:
http://www.physicsforums.com/showthread.php?t=658488
http://www.physicsforums.com/showthread.php?t=648312
http://www.physicsforums.com/showthread.php?t=410156
http://www.physicsforums.com/showthread.php?t=327169

3 of them are from the "similar threads for:"-feature, and I think you can find more with the search function.