This is about the best site DLTK-kids. Here you can make a calendar, print birthday cards and invitations, and a lot more.
By looking at what's available on Ebay, you can get a lot of ideas (check out the scrapbook pages!)

Shrinky Dinks
Here is a fool proof idea, but it requires some materials you probably won't have around the house: Kids love using Shrinky Dink material. It's plastic that you can either use colored pencils to draw or you can buy sheets that you can run through your inkject printer.
You can transpose ANY artwork or rubber-stamped image into a HARDENED PIECE OF PLASTIC...Magnets, Christmas Ornaments, Gift Tags, Key chains, ID Tags, Name Plates, Mobiles, Jewelry, Tie Tacks, Pet ID's, Toys, Shoe Decorations, Picture Accents, Greeting Cards, Stand-ups, Zipper Pulls, and Traced Photos are but a few of the CREATIVE items being personalized and made from SHRINKY DINKS SHRINKABLE PLASTICS...

For your Buzz Lighyear fan, compile some clip art onto one sheet, print on the special paper, let your child cut out and punch a hole, then bake it and you have a small plastic doo-dad that kids seem to be thrilled about. The plastic shrinks to about 1/3 the size, but ends up being 9 times as thick.

This is where you can find the paper: Shrinky Dinks
Starry Sky Ceiling (this will be a big hit!)
Also: It's really a neat idea to paint very small stars on your child's ceiling. Use glow in the dark paint in a very light color (white) and use a q-tip or other very small brush. Paint the stars all over the ceiling and you will get an effect of looking up at a starry sky. You will need to do the painting in the dark with a black light to allow you to see what you are doing. The white glow in the dark paint doesn't show at all on a white ceiling in daylight. A typical kid's bedroom only requires about 2 oz of paint.