This started as a game with my friends from high school, but I'm pretty sure I've never played with them. :-) My church friends now love it, and we play every chance we get (we even played in a bus once!). It involves going around a round-about repeated while giggling and screaming "Uno Mas! UNO MAS!" ("One more! One more!").
It's really fun (and funny). The problem is: you waste gas and don't go anywhere. You drive in circles again and again and again until the passengers get dizzy, the driver is bored, or another car comes.
Sometimes do you drive in circles repeatedly with God? Keep passing by the same spot but never really going anywhere? Sometimes you have to hit the turn signal and exit the round-about. It's not easy. Driving in circles is much more fun but moving on is much more productive.
Disclaimer: Do not play on big round-abouts with lots of cars nor at busy times of the day. Round-abouts in parking lots work very well. This blogger is not responsible for any injuries, dirty looks, nor tickets as a result of playing Uno Mas.