Yui
From MohidWiki
Yui is a suite of tools hosted by <goto>Yahoo</goto> that aim at improving the performance of web-sites. In particular the yuicompressor tool is extremely interesting as it minimizes javascript and css code by ascii manipulation (variable name shortening, space shortening). It also encodes the code to be almost unintelligible to the human eye. It is a good tool to use with jquery plugins.