Has anybody ever heard of the Military Simulation events with air soft weapons?

My son and I have played Air Soft for about 6 years now. It seems to be a good way for a grown man and his pre teen/teenager to connect. Well my son has joined the Army Reserves doing the split ops program. As a reward for graduating and doing so well I paid for him and I to go to a Milsim event in Oklahoma. It started on a Friday and ended on Sunday late. It was actually a lot of fun and somewhat realistic. I did not see much "action" in Desert Storm but I did get into a few skirmishes. The American Milsim company that put this event on really tried to make as close as they could to real military. Just wanted to know if anybody else has heard of these events?