Homemade Paint for Toddlers!

In my effort to foster creativity and prevent boredom (especially on a rainy day), I've started finger painting with my 17 month old son. I've tried several recipes for homemade paint on the internet, and I think I've finally come to the right mix. I used 1/4 cup all-purpose flour and 3/4 cup water as a tester. For bigger batches you can try 1 cup flour to 3 cups water. They store well in a sealed container in the refrigerator. Here's how to make good homemade paint:

Ingredients
flour & water (1 : 3 ratio)
~1 tsp salt
food coloring

1. Mix flour, water, and salt in a medium saucepan. Put the mixture on medium-high heat and whisk vigorously for a while, until the liquid is close to boiling and it starts to turn pasty. The amount of time depends on the consistency you want. If you want it more watery, you can take it off the heat earlier. If you want it more pasty, keep it on the heat to reach the desired consistency. I found it's really important to whisk well!
2. Take the mixture off the heat and let it cool for a bit. Scoop the mixture into little containers-- I like using the plastic egg cartons. Add food coloring to your preference in each of the containers. Voila!

I need more crafts and activities for inside the house. Any ideas?