This was a really cool place we checked out recently:
www.burbmom.net/northwest-regional-airport-blue-hangar-cafe/
We didn't do a tour like this other lady did, just met some friends for lunch, but it was fun. We enjoyed dining outside and seeing the planes land right before our eyes. I'm sure arranging a tour wouldn't be too hard as the hangar manager sounds nice.
California Pizza Kitchen gives tours. I believe the minimum age is 8, but you can call the Grapevine location to check.
Our Denton MOMS Club group has taken tours of Cici's Pizza, Cold Stone Creamery, Beth Marie's Ice Cream, Candy Haven & Kolache Haven Bakery, the local post office, etc. Costco in Lewisville gave us and the kids a great tour, even treated us to pizza from their deli and the kids got to decorate treats from their bakery in the employee dining area. Rocky Mountain Chocolate Factory will demonstrate how they make their marble slab fudge if you call to set up a time. Family eGuide is an awesome resource, as well. The Bison LLELA area sounds neat for a nature tour. www.ias.unt.edu/llela The Fort Worth Nature Center also offers some outdoor tours, including bison feeding hayrides. http://www.fwnaturecenter.org. Supermarkets will also give tours. We toured a new Kroger Signature store in south Denton, which the kids loved because they were given free samples at the deli, bakery, etc. Market Street does a nice job with their tours, too, from what I understand. I'll bet Central Market in Southlake would, as well. It's been years, but the Fort Worth Star-Telegram was a neat tour for my fifth-grade class. It was very cool watching the papers being printed before our eyes.