One of the books we (my children and I) read was about the solar system. After reading a book, we like to have a hands on activity. Today's hands on activity is using watercolors to recreate some of the planets. We did Earth, Mars, Venus, and our moon. We used glittery watercolors and it's extra sparkly and pretty (according to my toddler girl).
If you don't want to make a solar system, instead you can use watercolor paint over the majority of a sheet of white paper, allow it to dry, and you'll have nice stationary paper.
Total Time: Varies on your child + drying time