As I've continued to compile Would You Rather...? math posts, it has become clear that many of the decisions we make have a lot to do with the units in which they are presented. If we can get kids to play games with units more often, my conjecture is that we would have contributing members of society who are less susceptible to manipulation of the media and marketing. We would have contributing members of society who are more adept to the information presented to them. We would have contributing members of society who, ideally, look to a value's units before rushing to a judgement. Ideally.
I like the 100+100 because it seems "easy" for kids, but use whatever you think would be the most interesting for your group. Once a week, put up a different solution. The trick, the game, the goal, is to find out what units are being used to reach the solution.
Here are a few others:
Oh, and good luck with "I'magonna Google that".
Happy Unit Fishing