Also, I love Alex craft box kits (you can get them pretty cheap at amazon.com). They have several boxes with ready-to-make crafts and instructions with all the supplies you need. I have several of the kits on hand in case I am not feeling creative.
One of my son's (2 yr old) favorite craft activities is creating his own scene. I use construction paper in light blue for the background, then cut out green construction paper with grass-like top and let DS paste to the background, then I use stickers (you can get sticker books w/like 600 stickers for a buck at craft stores) and let DS put them on his scene and/or I'll cut out different things like house shapes (including window and door shapes), a sun, clouds, trees, flowers... and let DS glue them on the scene. We can do this with dark blue water (just cut the top of the construction paper wave-like), or we can add a street in the grass scene, etc. He is at the age where he loves the glue stick so this is a craft he adores and since we can change to scene and add new shapes or stickers it hasn't gotten old yet.
We also do homemade cards, like thank-you cards, valentines, Easter out of construction paper, stickers, and cardstock. It's fun for him to make, plus it allows me to teach him about the holiday/event and learn the importance of giving of himself to others.