I've been working with ASP.NET 2.0 for a long time now and I thought I'd seen most of it. Today I found something that must have flown under my radar all this time: the Health Monitoring API. Functionally this API is similar to log4net and the Enterprise Library logging Application Block. Although both of these work well I prefer functionality that comes "out-of-the-box", because you don't have to do anything to get it, it works, and your pretty sure it'll be kept up to date by the folks in the product team(s). So even if you're using another logging mechanism, be sure to check out the Health Monitoring API. How To: Use Health Monitoring in ASP.NET 2.0 from the  Pattern & Practices group is a good starting piont.