I usually don't associate BBQ with good culinary experiences, but define what you're looking for. We have chains, such as Memphis BBQ, and fancy ones.
What origin of BBQ? A Mongolian BBQ, a Korean BBQ, or something else. Please set your parameters better.
Also set your price range.
Assuming you want American BBQ, here is one:
http://lasvegas.citysearch.com/profi.../bbq_shak.html
There are at least two Memphis Championship BBQs' which I personally find very average but some people like. Give me a call if you're in town.