Homemade Baking Powder

So, you ran out of baking powder?  No prob, Bob!  Here's a homemade recipe...

1 tsp baking soda
1 tsp cream of tartar

Whammo!  You've got some baking powder.

So, carry on.  Finish baking whatever you started without having to run to the store.

P.S. washing soda isn't a good substitute!