What's Gumby?
Gumby is geolocationing for the masses through a public API which means anyone can use it in whatever way they want.
The Gumby API is currently available in the following response formats:
Does it work?
Well, hopefully - Gumby is saying that you're in 
UNITED STATES.
But there's no guarantee that Gumby will find the country of the IP, but tests so far in the beta period have been successful.
Documentation & Examples
Currently there is not that much documentation available for the Gumby API, but it should be pretty straight forward if you've messed around with pretty much any other API.