Microsoft Corporation - 8.14MB (Freeware) - BETA
Microsoft Silverlight is a programmable web browser plugin that enables features such as animation, vector graphics and audio-video playback so you can experience rich Internet applications.
Silverlight offers a flexible programming model that supports AJAX, VB, C#, Python, and Ruby, and integrates with existing Web applications.
It supports fast, cost-effective delivery of high-quality video to all major browsers running on the Mac OS or Windows.
Download: Silverlight 4.0.50303 RC