Take her to the dollar store & give her like ten bucks to spend on statues or figurines or whatever. Tell her to pick out stuff that she's not that into (lets hope she doesn't have a thing for dollar store figurines, anyway). Buy some stuff for yourself -- ceramics or brittle plastics are the best materials for this.
Drive to a somewhat busy street (somewhere with at least two or three cars every five minutes works just fine), take out the lawn chairs you've had stashed in your car for this moment, set them up in a nice spot where you can see the road, and have her take a seat. Then line up all the figurines and shit you guys bought in the middle of the road.
Walk back to her and have yourself a seat, pull out some beverages & cheese, and watch cars run the stuff from the dollar store over.