I know its a bit late but you may be able to use these at a later date:
Put food colouring in bubble mix and get the kiddies to blow bubbles onto paper. The bubbles pop and leave colourful patterns on the paper.
Instead of normal painting try putting glitter in the paint to get different affects.
The good old fashioned pasta necklaces always go down well with the kids as well.
Draw with candles onto paper and then paint over them with water based paints to revel their invisable drawings.

I hope this is of some help