I recommend the 250 points and 500 points problems of topcoder(http://www.topcoder.com/). Some of the classical puzzles are so straightforward, while more effort is needed to find the tricks of the problems on topcoder.
Async is a very nice feature of C# 5. I think both C# team and ASP.NET MVC team are keeping absorbing the greatest ideas from the community outside Microsoft, which makes life easier.
I recommend the 250 points and 500 points problems of topcoder(http://www.topcoder.com/). Some of the classical puzzles are so straightforward, while more effort is needed to find the tricks of the problems on topcoder.
Async is a very nice feature of C# 5. I think both C# team and ASP.NET MVC team are keeping absorbing the greatest ideas from the community outside Microsoft, which makes life easier.