My mom's club is having a potluck playgroup next week and the theme is "cool treats". Anyone have any ideas? I'd prefer something that isn't frozen, because it's over 100 degrees here every day and I have to drive to the mom's house. Easy and not too many strange ingredients would be good, too, though it doesn't have to be overly kid-friendly (the food is mostly for the moms while the kids play). Thanks for any ideas!