Paul - there are several families which operate many restaurants in Houston; Pappas is the biggest operation now and probably the best known outside the area, though. Others include the Mandolas, the Cordua group, and the Laurenzo's (Ninfa's). Formerly there was a Vallone group, too. Landry's was originally started by a group of 4 families from Lafayette, altho none of them have anything to do with it now.
The Pappas group also includes Pappas Steak House and Pappas Grill (steaks and chops), Pappas Burger, and Yia Yia Pappamia (Greek). There's a Pappas Pizza in Dallas.
Another one, which was actually their first restaurant venture I think, is Dot Coffee Shop. There's only one left but it is an excellent diner, open 24 hours, with fantastic meat and three lunch and dinner specials. It's on I-45 South at Woodridge, just inside Loop 610.
The Original Pappas formula was 'generous portions of good food at modest prices.' The prices have gone up! They used to practically force take-home containers on people in the early years; their portions were uncommonly large and lots of people were shy about asking for doggie bags back then.
You might be interested to know H.D. Pappas, the patriarch, came from Greece and operated restaurants in Tennessee and Arkansas before coming to Houston.
I know someone who swears the Pappas ribs are boiled but I don't know how to detect that. The best things at Pappas BBQ to me are the sides.
http://www.pappas.com/