You are probably thinking Balls or Ez's or the Purple Cow--something more kid-driven than kid-friendly. But we are thinking food locales that may cater to kids but actually target the adults of the family, those over the age of, say, 5. The new Tin Star on Belt Line Road meets our criteria down to the last available chip. You've got your big-guy Southwestern cuisine, served up fast, done up tastefully and modestly priced. And your prepubescent fun food--taco cheeseburger, hot dogs, chicken fingers--tasty morsels all. The stand-in-line service lends itself to kids, particularly those with short attention spans and hungry appetites. And there are slurpees for those who think young, and Oreo cookies for those in search of a sweet ending to this fine but casual dining experience. Standard-issue coloring books and crayons are available upon request.