ASP.NET output caching

http://stevenharman.net/blog/archive/2006/05/13/Custom_Output_Caching_in_ASP.NET.aspx

Tip/Trick: Implement "Donut Caching" with the ASP.NET 2.0 Output Cache Substitution Feature

"For anyone interested in seeing the above in some real code, subText uses this very technique to cache several of the user controls needed to render the UI..." - http://subtextproject.com/