Bookah is the best of the Pittsburgh hookah bars, although that's not saying much. Still, it's an enjoyable spot to spend a few hours.
At night they turn the lights off and the atmosphere is more clubby and college-y than relaxing, although it's not too loud. It can get a bit cramped, so you might have to do some gymnastics to get to the counter. Service is friendly and prompt, although it can lag a bit during the busy weekend-night hours. Seating is comfortable, even if you're not on the couches.
The hookah is overpriced but awesome. I always have an enjoyable smoking experience at Bookah. Here they use good quality tobacco, well-maintained pipes, and natural coals that are frequently adjusted for optimal smoking.
It can get a bit crowded as the drunks stumble in towards the end of the night, but the quality of hookah and service you receive is superb. This place closes at 2 but we've been here until 3:30 without issue. Definitely stop by.
Oh, and try the fries. They're lime-salted and good to munch on while smoking.