Not sure if making plasticine appear to come out of your kids noses is quite 'arts and crafts' enough, but we have been having much fun with this today: www.samanimation.comso thought I would share the link.
It is cool free software to make animation movies with dough, fruit, paperclips, barbie dolls or whatever you want to animate...(it is the same as the software that comes with the Klutz Animation book, which is good, but you don't actually need the book...).