I'll shamelessly plug myself:
https://bitcointalk.org/index.php?topic=1345538.0

But there are others,

A German group that has hit 4 blocks:
https://bitcointalk.org/index.php?topic=1318387.0

And smaller ones that are trying to get up and running.


I must warn you though, invest at your own risk. Because this is pretty much gambling, but gambling on if you will mine a block or not.