Have all the students stand up at their desks and find a student to answer the first question (or alternatively ask for a volunteer). Ask the student a question, it can be true or false, multi choice or anything related to what they’re currently learning.
If the student answers correctly they can choose either their row or column to sit down with them, if they answer incorrectly nobody gets to sit down. Continue the game until everyone sits down.
It’s always fun to see which of their friends the students will keep happy when choosing either their row or column. You can control the game as you see fit by giving lower level students plenty of chances and asking bright students more difficult questions.
To make things more challenging you can introduce a penalty system where a wrong answer forces both the row and column of that student to stand up again. There are a lot of variations to this activity so feel free to adapt it your students, classroom and teaching style.