Salt Painting: paint glue lines on dark paper. Sprinkle with salt and let dry. Paint with watercolors or food coloring--the paint will spread thru the glue lines. Experiment mixing colors by dropping one color next to another.
There are hundreds of channels devoted to Minecraft, including popular but edgy ones such as Yogscast and SkyDoesMinecraft, and it's hard to know which ones are good for kids. Although you could download an app such as KicVidz, which curates only kid-friendly Minecraft videos, you know your little fanatic will be begging -- and searching YouTube -- for more.