(Maybe best for a community wiki, can someone convert please?)
I'm interested in the idea of online learning communities such as Java BlackBelt, for those that haven't heard of it, you create a profile, take "exams" and earn "ranks", similar concept to StackExchange sites except exams/quizzes are substitued for questions
My question is, what other sites/resources are there like this? Is there a similar setup for .NET, c#, SQL Server, and others? What sites do you use for testing your knowledge on programming technologies?