Glimpse is an open source tool that allows you to debug your ASP.NET web site or web service right in the browser. Glimpse allows you to “Glimpse” into what’s going on in your web server. In other words what Firebug is to debugging your client side code, Glimpse is to debugging your server within the client.
Currently, it works for any ASP.NET website and even has specific extensions for specific frameworks like (ASP.NET MVC, etc.). Besides just supporting frameworks such as these out of the box, Glimpse has an architecture that fundamentally supports the future development of Server side implementations of Glimpse for other non-ASP.NET based system in the future.