Woot

Definition
Also spelled as "w00t".

An exclamation of joy, happiness, or other positive emotions. Pronounced "whoot".

Thought to originate from certain MMORPG worlds as a contraction of "Wow! Loot!", or that the phrase came from Counterstrike players and that it was an acronym for "We Owned the Other Team".

In truth, the exact origins of the phrase are unknown.

Usage
"I just unlocked the last level! woot!"