Lunch near Stafford Center (Houston)
I'd go to Huarache Azteca. Basically a taco stand/joint, and arguably the best in all of Houston. Tacos and huaraches are both outstanding. You're going on a weekend so get the lamb, it's unbelievably tender and has incredible flavor.
Tornado Burger is also nearby and they have burgers similar to In-N-Out burger.
Absolutely agree with Huarache Azteca Express; it's very close and will probably be very busy. I'd pass on Tornado unless you're just really jonesing for a burger for some reason.
For something different, in the evening only, drive up Murphy/1092 toward Houston, cross 59 and then through one more light and look for Bansuri Indian Food Corner on your left, a truck dispensing the street foods of Mumbai. Open only a few hours in the early evening and closed Sunday; be prepared for a long line.