I am tired of doing typical CRUD programming type applications. I would like to work on some interesting (not too hard) programming problems. Are there any sites out there to help me exercise my brain?
Project Euler: http://projecteuler.net/ is a nice collection of randomly interesting problems.
Somewhat related (not always programming, but generally interesting to programmers) is the IBM ponder this site: http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/pages/index.html
One other great site is ... stackoverflow.com :)
There are some really great questions asked on this site. I find it fun to pick some of the questions and develop answers for them. Often I pick a theme. For instance for the last week, I've tried to solve as many problems as possible using only a single LINQ expression.
I've used the problems on Ruby Quiz before. Other than that Dave Thomas' CodeKata and see if there is a Coding Dojo near you.
Check DotNetPerls they have a good selection of problems and solutions focusing in C# programming.
I also like the C# Brainteasers from Jon Skeet, good code snippets to read and learn more about the language, some have very interesting and surprising results...