I have tried to use some of the widgets in JQuery UI on an Asp.Net MVC site without luck.
JQuery UI
Asp.Net MVC
For example the basic datepicker from jQuery UI -
I've got a write-up of this with MVC 3 here: http://blogs.msdn.com/b/stuartleeks/archive/2011/01/25/asp-net-mvc-3-integrating-with-the-jquery-ui-date-picker-and-adding-a-jquery-validate-date-range-validator.aspx