Pumping gas.
Get us a picture when you are in uniform.ATI - Driving the chemical reaction revolution

Clean Jim's house.
That's a job well worth at LEAST $50US/hour.ATI - Driving the chemical reaction revolution

Bah.
As far as summer work goes, you only have a couple options (and no, moving my house to Texas isn't one of them).
Depending on where you're staying means a lot about what job you may end up with. Is it a tourist destination or near one? Is it near any big cities or perhaps in one? Or is it out in the middle of nowhere, with nothing but oil fields and cattle to look at?
Then, you have to figure out WHO is getting you the job. If the people you're staying with in Texas are going to help you find a job, then they'll be able to tell you what's around, and what's worth looking into. It'll also help coordinate work schedules with whoever you're looking to see, since you probably don't want to spend more of your summer working than actually doing what you want to do.
What type of job you get will definately depend on where you are though. You could easily be working at a grocery store (like Gest said) or possibly working retail at a local mall. If you have, or can get any experience as a waitress, you might want to try looking for that as a job. It'll probably stress you out like few other jobs can, but that IS where you're likely to make any decent amount of money. Otherwise, expect anwhere from $5.25 to $6 an hour at most places...