yeah there is you can check out
http://www.yourhummeradventure.com to receive their newsletter and local events along with statewide events coming up.
You may also want to check another great forum that started up in the North Texas area called
http://www.hummercommunity.com. There is a good amount of folks doing events around the North Texas area from Mineral Wells, AGR Wheeling Ranch, Barnwell Recreation Facility, and also Hummer Happenings at places like Shiloh Ridge and looking at Grey Stone Mountain.
Where did you purchase your vehicle? There are a bunch of Hummer Happenings coming up that are supposed to be pretty good in the North Texas area.
Take care...