Ask HN: Exercises for Regular Expressions?

Apart from what is available in the books about Regular Expressions, are there any web sites / blogs series / etc. with a bunch of exercises that are somehow more "real world" that the ones in most of the books?

My specific problem is that currently I don't have specific needs / areas where I can exercise what I've learned about RegEx, and yet somehow I want to exercise more even with some other applications like other people's examples... Or writing a simple program for processing some text that can be implemented by heavily using RegEx?

Thanks in advance