Name of the Game: Yellow Car Bingo
Rules: One point is awarded to player who spots a yellow, road-worthy vehicle (only certain road-worthy tractors are applicable) and says "Bingo". Games lasts for the duration of the car ride (from when the engine is started to when the engine is shut off). Game can be changed to accommodate different colors (i.e., White Car Bingo, Red Car Bingo, etc...)
Fun Possibility Level: Gobs and Gobs
Warning: You may start to play when you are alone in the car (and not with your 5 year-old nephew) and randomly yell out "BINGO!" Just like I did today. At least 6 times.