You can try this C# .NET 4.0 port of Sean Luke's ECJ (Evolutionary Computation in Java):
http://branecloud.codeplex.com
It is very flexible and powerful software! But it is also relatively easy to get started because it includes many working console samples out-of-the-box (and many helpful unit tests that were developed during the conversion).
As noted above, if you program in Java, you should visit Sean Luke's site directly:
http://cs.gmu.edu/~eclab/projects/ecj/
It has been under active development for 13 years!
Ben