Buy two 50lb sacks of lime, some rope, and a trash bag. Take her out somewhere secluded, make sure that the radio in the car is off. Once you pull over to the destination, ask her to get out as you have a surprise for her. Take her back to the trunk, open it up, give her a second to realize what is in there, then nudge her like you're going to shove her in. Once she stiffens up, break out a smile and say "Gotcha!!" Then go watch a Kevin James movie.