“Need to use our AJAX controls in a custom Sharepoint 2007/2010 implementation? Not a problem at all. RadEditor, RadGrid and the rest of our ASP.NET AJAX components can also be plugged very easily into Sharepoint 2007/2010 visual/dynamic web parts, or placed directly into Sharepoint pages/user controls.”
Telerik Sharepoint 2010 Demo Site: http://sharepoint.telerik.com/Pages/default.aspx
You can play with RadGrid web part after login with:
Here http://sharepoint.telerik.com/silverlight/Pages/default.aspx you can find screen casts from Sahil Malik, how to use Telerik Silverlight controls in Sharepoint 2010, together with Sharepoint client object model. Enjoy!