I heard this fabulous speaker at MOPS who was an art teacher before coming a full-time mom. She gave all sorts of fun art related activities to do with the kids. One of these was Oil Pastels. I used my 40% off coupon at Michaels and bought these oil pastels. Only $5 though, so with or without coupon it's not a pricey investment.
Anyway, the kids have fun experimenting with these. As our speaker encouraged, "It's about the process not the finished product!"