Some ideas:
Bowling (I remember seeing one in Grapevine Mills that was dark and had a lot of black lighting and neon), arcade (Gameworks?), if you're in Fort Worth I know they show movies downtown outside on a large screen one night of the week, museums if they're artsy....Cool exhibit at the Modern in Ft. Worth right now...botanical gardens, Speed Zone, Putt-Putt golf, Chucky-Cheeses (Kinda goofy, I know....but sometimes it's fun to be a kid again. Depends on the girl). Does Dave and Busters have an age requirement? I don't remember. Eat at Rain Forest Cafe. Is the Magic Time Machine restaurant still around? Those are different and fun. Hard Rock cafe in Dallas....Walk around and look at all the guitars and music paraphanelia or Planet H'wood. Restaurant at the top of Reunion Tower (May be too expensive...if it is, I think you can just go up there and see the view. I usually take them to the revolving bar so I'm not 100% sure on what time they close the viewing platform). Naked twister. New Fine Arts----tell them to pick out a toy
Learn to cook one meal really well. Take her with you to the grocery store to buy the stuff and cook for her. Or, cook it together and then use it to qualify her.
Most cities have a paper that comes out the latter part of the week with activities listed. In Ft. Worth, it's called "GO". It's in Friday's Star-Telegram each week. There's also a local mag called Fort Worth Weekly you can find around town....kinda like Dallas Observer. You can always find things to do using those sources. Fort Worth Weekly has a website, but the actual paper is better IMO.
Have fun.