Art Project: Printing Circles Supplies:
lids (from milk jugs, drink bottles, canning jars, etc, etc)
marker caps (from dried out markers--save the caps! use the cores to make liquid watercolors !)
(other ideas for circles: plastic easter eggs, empty & washed medicine bottles?, film canisters if you have a stash of those still leftover.... look around your supply cupboard and I'm guessing you'll find some circles.)
Stuff to stick into sticky stuff is surprisingly entertaining!
Art Project: Playdough Monsters (inspired by The Artful Parent) Supplies:
play dough (I made my own (recipe below), but commercial play dough works fine)
any other odds & ends you have on hand -- buttons, sequins, pipe cleaners, straws...