I picked one of these up. But I still find myself missing the call control of having an asterisk box handle the number.
You can block a number or direct it to a specific phone or voicemail with google voice's web front end.
You create a contact, edit the google voice settings for that contact, and select "block phone" for example
Unknown to many, you can even match the CID text field to direct/block ANONYMOUS PRIVATE etc.. just enter those in the phone number contact field.
One thing that I am able to do on numbers answered by my own Asterisk box is pattern match caller id. Also known as caller id wildcarding.
You'd use the standard asterisk dial plan.
http://www.voip-info.org/wiki/view/Asterisk+Dialplan+Patterns
With this I was able to match a whole area code. So if I was getting a lot of bullcrap calls from an area code I could send all numbers in that area code to voicemail or block them.
Sadly google voice doesn't support this yet.
Either of these would be valid patterns for area code 920
_920
or
_920XXXXXXX
I tried entering these as contacts hoping they would work :-( Maybe someone else knows some other trick?
If not, I think this would be a great feature to support. I encourage anyone else who thinks so it, to leave it as a suggestion as I have.
http://www.google.com/support/voice/bin/static.py?page=suggestions.cs