As you may have noticed, I'm on a performance kick as of late.  Here's one more tip for you.  Compressing / Minimizing / Shrinking your JavaScript files can decrease download times.  Putting your scripts together in one file will also help performance.  Here's a good article on reducing page load times from a Google engineer.  This article is the source for most of this wisdom.

So armed with this new knowledge I went in search of some pre-shrunk versions of the Prototype and Scriptaculous JavaScript Libraries.  This is what I found.  I still need to test the library but it seems promising.  I will keep you posted.