Like KC Jayhawk said, you DO NOT have to know anyone competing to enjoy the American Royal BBQ.
Friday night, which is the best night for a "party" atmosphere, it costs about $10 to enter. Then many of the bigger team spaces will allow you to enter for $10 or so, and then it is all you can eat and drink once inside that space. They will also have bands and fun stuff like that. And the food is amazing.
I personally know members of Where's The Smoke and Boneheads. Both have one of the biggest spaces available, and it is a great time to hang out. Bring friends, and most of the money to enter their team space goes to charity.