Create Modal Pop up on button click in ASP.Net

I want to create a good Pop up on button click. pop up whose "height" , "width" can be controlled. It can be either Jquery pop up or Javascript.

In this pop up I want to use asp.net controls and ajax (as normal webpage functionality but in form of pop up) also its background should be little blur when pop up is open.

How can i create such pop up?

Please reply.