Shari Griffin was tired of strapping her own two young sons into molten car seats in the summer, in Phoenix. What could she, a stay-at-home Ahwatukee Hills mother of two, do to make those contraptions kinder to her babies' bottoms? She could put ice packs into a cloth cover, and then put her creation in the car seats before putting her children into them, that's what she could do. Voilà! The Cold Seat was born. The car-seat-size ice pack comes in four patterns, and can be rolled up and stored in the freezer between uses. Griffin sells her invention for $49.95 a pop through her Web site and over the phone. Sure, cooling hot seats with ice packs seems obvious in hindsight, but you didn't think of it. Besides, you have to give Griffin a lot of credit for figuring out a way to sell ice for around $25 a pound.