Myghty is a Python based templating framework originally based on HTML::Mason, the enterprise-level framework used by Amazon.com, del.icio.us and Salon.com,
Sajax is an open source tool to make programming websites using the Ajax framework — also known as XMLHTTPRequest or remote scripting — as easy as possible. Sajax makes it easy to call PHP, Perl or Python functions from your webpages via JavaScript without performing a browser refresh. The toolkit does 99% of the work for you so you have no excuse to not use it.
jMaki is an Ajax framework that provides a lightweight model for creating JavaScript centric Ajax-enabled web applications using Java, Ruby, PHP, and Phobos.
Open-jACOB is a free framework for building a new generation of richer, more interactive, database driven, highly personalized cross-browser web applications.
jQuery is a new type of Javascript library. It is not a huge, bloated framework promising the best in AJAX - nor is it just a set of needlessly complex enhancements - jQuery is designed to change the way that you write Javascript. What is jQuery?