Our youth group did this as a competition--who could create the best tree. We added real lights too. They loved it! Lots of laughs, and no real need to buy supplies, other than crepe paper. Use what you have.
Why not make a fun holiday workbook for the kids to work on over the break? Add a few Christmas Mad Libs, a few math coloring worksheets and they will still be doing some school work, but have fun too!