It's a multiple-choice powerpoint quiz where students guess the capital city of several countries. I was asked to make this as a warm-up activity for 2nd-year high school, though I'm sure it would be suitable for JHS also. When I used this activity, I put students in small groups and gave each group four pieces of paper with A, B, C, and D printed on them. Then, for each question, I gave 30 seconds for students to discuss and then had all groups hold up the paper corresponding to their choice. I awarded one point for each correct answer and tracked the score on the blackboard.
There are 11 countries in total but you can of course add more if you want it to be longer.