You’ve probably stumbled upon a navigation powered by some jQuery effects during your web adventures. Of course you then ran your mouse back and forth over the navigation really fast to watch the animation repeat itself over and over and over again. The natural queuing of animations/effects by jQuery makes the typical animation super easy to code and move on to more important tasks. However, sometimes the animation queue just gets in the way.
The following article has an example of how to create animated navigation without the animation buildup: Quick Tip: Prevent Animation Queue Buildup » Learning jQuery – Tips, Techniques, Tutorials