Are there any good tools to see how much data (or even better the values of that data) is in my HttpContext.Cache?
Update; The previous link to Scott Cate's article is gone now. Since there was quite a bit of code there (which is not easy to summarize here without reproducing the entire blog), I'm updating this answer with an easier choice: Aspy
Aspy is totally free ASP.NET Session and Cache online viewer. It can be integrated with any ASP.NET web application including ASP.NET MVC and Web API. It is ready to use right after the installation. More detailed description is available on our website:
Available on NuGet and needs no coding at all.
PM> Install-Package Aspy
Short Screencast