Make Your Own Snowflake
http://snowflakes.barkleyus.com/
 

The Art Zone
https://www.nga.gov/education/kids.html
Interactive art you can make online. Downloading needed.
 

Artsology
http://www.artsology.com/
Interactive online art activities. Very cool stuff!
 

Tate Kids
http://www.tate.org.uk/kids

Tate Art Institute for the UK has some cool interactive art activities for children.
 

Scrap Coloring
http://scrapcoloring.com/
Online coloring and scrapping.

Aminah's World
http://aminahsworld.org/
Create original art with colors and found objects.

Toy Theater
http://toytheater.com/category/art/
Lots of interactive art activities from doodling to shapes.

Artsonia
https://www.artsonia.com/search/
Explore various school art projects. Get ideas and create!!