High-level Python Web framework

Website: http://www.djangoproject.com/

Ajax opensource framework

Website: http://subway.python-hosting.com/

A complete office suite usable via your browser.

Website: http://ajaxoffice.sourceforge.net/

Connecting Wikipedia articles with their locations

Website: http://www.placeopedia.com/

The official Rails hosting service is accepting new clients again!

Website: http://www.textdrive.com/

No server-side programming needed

Website: http://verens.com/archives/2005/08/12/ajax-powered-gallery-with-no-server-side-programming/

Using XMLHttpRequest with php and mysql

Website: http://www.webpasties.com/xmlHttpRequest/

Open source tookit for javascript and AJAX

Website: http://dojotoolkit.org/

Flickr AJAX gallery

Website: http://gallery.beseku.com/1/

A nice place to start

Website: http://dhtmlnirvana.com/ajax/ajax_tutorial/