I like this one for its simplicity and the fact that student choice is integrated into the activity. Students decide what level they need to start at. This is a great form of formative assessment (self-reflection and activating students as owners of their learning).
The Leprechaun Complete the Square Game comes from K. Fouss. Different complete the square questions are written in the colours of the rainbow, with the more difficult ones being farther along in the spectrum. Students can use this as review or preparation for a summative assessment. Ms. Fouss shares the sheet students use to write down their questions and answers, but as far as I can tell, you’ll have to make your own questions. I’d just pull them quickly from whatever textbook you use.