I do something similar to this but instead of using lots of scrap paper I have a supply of coloured A4 paper laminated.
The groups/pairs are then given a whiteboard pen.
I call out a review question - generally a vocab question. The first group who raises their 'board' with the correct answer (must have correct spelling) gets the point.
The students then have to wipe the board clean (so take in some tissue for each group).
A new student in the group now holds the pen. Make sure they change writers otherwise the strongest student does all the work.
When you ask the questions you might ask for more than one word - for example - 'three phrasal verbs using get'.
I have used this a lot for vocab review (general vocab/collocations/phrasal verbs/word families/dependent preopositions) and the students seem to love it - adults not children
