Chris' Magic: The Gathering Card of the Day!

Disempower

Return target artifact or enchantment to the top of owner's library.

This is a very versatile card. Disempower is not bad at temporary permanet removal, but can be very sneaky with any of the following:

Gauntets of Chaos/Juxtapose
Trade artifacts with an opponent with either of these cards. Disempower the artifact you just gave your opponent. Disempower doesn't care who controls the artifact, it just cares about who owns the artifact. Send the artifact back to the top of your library so you can just draw and cast it again next turn.
Triskelion
Shoot off the 3 tokens that come with Triskelion at something, then Disempower the Triskelion to cast it again next turn. I'm sure you can think of plenty of things to do 6 damage to.
Steal Artifact/Conquer/Control Magic/Steal Enchantment...
Have you ever noticed that as soon as you steal a permanent from an opponent, they usually play something you'd rather have a turn or two later? Return whatever theiving enchantment you are using back to your hand and steal the more appealing permanent.
Bizzare of Wonders
This is one of the cheapest ways to clear out all player's graveyards a few times (I'm not going to get into why you'd want to do that tonight).