I love my 7th-graders! Today was the second time I've played games with them on a Friday afternoon, and they absolutely go nuts for it every time.
One concern I always have during a group game is that only the kids who are up for their turn are engaged. Today I improved that by letting TWO kids from each team go up together, and they can only collaborate AFTER they have both tried the problem independently. When they ring the bell, both people should already have written down the answer on their paper, and I'll randomly call on one of them to EXPLAIN their answer. (So, they had to confer before ringing the bell, and the stronger student was always eagerly explaining to the weaker student how to do it.)
The problems built up in difficulty, so I'd always make sure all students from the class understood the explanations to the previous question before starting another round. Students at their desks were also practicing because they didn't want to be the person to hold their partner up when it's their turn. Overall, the rotations went twice as fast, and everyone was constantly engaged.
By the end of the 80-minute period, even my weakest students were getting through the problems by themselves, and EVERYONE WAS SO EXCITED TO EXPLAIN THEIR ANSWERS! It was great!!
Grab the file here. This one was on filling in missing numbers into linear patterns, and some of it involved integers and decimals. The kids were brilliant! (We also had two exchange students from China playing with us. It was COOL; one of them explained to me in Chinese, and I translated for her in real time for the class, and high-fived her after that round! It was sweet.)