Are there any good parsing libraries for .Net?

Question

I'm looking for something simple to use where the grammar is easy to define.

Answer 1

Although I've never used it before, ANTLR has C# runtime.

Answer 2

Just found out about Irony. Used for writing DSL.
Thought I would add it to the list.

Answer 3

If you use F#, check out FParsec.

Answer 4

Give a look to Coco/R for C#.

Answer 5

System.Text.RegularExpressions?