Open UserControl As PopUp on ImageButton_Click Or Whatever Else Will Work

I have an ASPX page.  On this ASPX page, there is an image button.  

I also have a user control (ASCX).

Upon clicking the image button, I would like the ASCX to pop-up in a modal dialog box.

I have the AjaxControlToolkit in my solution.

Is it possible to open an ASCX control from a button on an ASPX page?  

I've tried several approaches with no success and am looking for fresh ideas.

Thanks, cj