cool Web2.0 free technologies

http://en.wikipedia.org/wiki/Prototype.js
http://en.wikipedia.org/wiki/Script.aculo.us
http://en.wikipedia.org/wiki/Jquery
http://livepipe.net/
http://www.phpflickr.com/
http://www.fpdf.org/
http://magpierss.sourceforge.net/
http://keithdevens.com/software/phpxml
http://www.phpcaptcha.org
http://www.openx.org/
http://tinymce.moxiecode.com/
http://openinviter.com/