If you have your entire family all together in one place, put them to work. This time of year is a great time to do some spring cleaning. Set up a family "Spring Cleanout Challenge." Give each person a goal -- perhaps you need your tween to get rid of the old toys he or she doesn't play with anymore. Maybe your kids have outgrown clothes and need to prune their closets. Or you might have a lot of old paperwork that needs to be filed or shredded.
Once everyone has a goal to achieve, let them loose with trash bags, boxes, cleaning supplies and whatever else they need to get the job done. Set a time limit so it doesn't drag on all day and all night. At the end, reward everyone with some pizza and plan a family garage sale. The kids will be much more willing to pitch in knowing that they might get some cash at the end.