ALARMING - Parking Ticket gag
These tickets are alarming when first spotted, the "victim" always does a double-time walk up to the car, then the other half of the fun is when they read the list of possible infractions on the back, such as "Parked in own driveway" or "Stopped for a kiss" - 31 different infractions or write one in. Put comments in the top section, lots of options for extra fun. This is a good one to pull on someone who got a ticket recently and whined about it incessantly.
Your "victim" will really think something's up if they see other cars cited. Measurements are approximate.