The only real place we frequently go that I need something extra for entertaining, is church and grocery shopping. For church we always bring some crayons, or colored pencils, and notepads, snacks, a bottle, and random toys (usually the ones from fast food kid meals). Also since Daddy is with us at church, if we really need it one of the girls will get to play games on his itouch. We've got some fun preschool/toddler games, like matching, shape games, etc.
Grocery shopping, I'm usually on my own, so I don't have the itouch with me. If I know we're going to be there for awhile, I let the Princess' pick a toy to hold. Then they can play with it while in the cart, but when we get to checkout, I just let the cashier know we are not buying it. Writing it up it sounds like I'm taking advantage of the store, but it's not like that really. The toys don't get dirty, or harshly played with. Mostly they just hold them.
For Princess V and Princess C I try to have them walk by the cart. It helps them get some energy out, and not feel too confined. Princess R is more difficult to entertain. She always manages to shimmy out of the buckles and stands, turns around, tries climbing out, of the cart. She is going to be a little escape artist! So having something for Princess R to hold is essential for my sanity, and her safety!
For car rides, I always let the Princess' bring a toy from home. They know they can bring it in the car, but when we get to our destination the toy must stay in the car. This helps keep special toys from getting lost, because trust me, they will get lost when brought into a store!
Future topics - Do you use charts with your toddlers? Reward system? How's it working out?