washi tape has a definite place in our house. it is pretty much one of the things we can't do without :) We have used it in cards (here too) and packaging.. but recently, we have found joy in how it sticks marvellously on walls, and yet does not peel off any paint :)
here's another idea for washi tape, and also for occupying an over-active cant-stop-moving toddler if you have one. use washi tape and stick a thread to it, den stick the thread on a beam or ceiling.
it bought me 3 minutes of free time. maybe it will buy you more :)
tip: if your child has a racquet, you can adjust it higher up and teach him to swat at it :) PP's brilliant idea.