Dallas is a great city (if it's in your driving path), mostly for the food and bars. That Kennedy exhibit though... ehhhh. I took my wife and mother-in-law to that thing last year and I'll be honest with you, it's fucking boring. It's interesting when you see all the stuff about the space race and stuff, but about half way into it, you'll probably just quit listening to that headset because it just drones on and on and on. It's not so much about the assassination, it's about his entire fucking presidency. And you can't even look through the window Oswald fired from because they have that whole corner of the building encased in bullet-proof glass, but you can look out the window that's exactly one floor above. They even have an "X" painted on the street where the bullet struck JFK in the head. Dallas takes very eerie pride in the fact a president was killed there.
The Flying Saucer Bar is great, there's about 3 of them. I recommend the one by Lake Ray Hubbard, also known as "Lake Flying Saucer". They have 300 beers on tap there from all over the world. Decent food, but the food isn't what you go there for. You know?
Also Six Flags over Texas in Arlington is a lot of fun. Just be careful, someone died on the Texas Giant rollercoaster last year when the harness opened and ejected some woman 100 feet in the air. Mr. Freeze is my personal favorite.
Deep Ellum downtown on Elm Street is where all the local bands play, but honestly it's went downhill the past 10 years. There's still some decent bars and good restaurants though. I recommend Cafe Brazil.