I have declared today to be an Official Rainy Day. Birdman and Lightning McQueen are baking oatmeal cookies. The following subjects are surreptitiously being taught: math - measurement, time, sequencing, multiplication, fractions (I had them double the recipe because we love cookies). Language arts - reading comprehension, following directions, vocabulary. Science - baking as chemistry; how do all those ingredients turn out to be cookies? I suppose there's probably some social studies in there too, since they are having to work as a team (two people are the smallest form of 'community' there is, you know).
In case you want to declare a Rainy Day and bake some cookies, they're using the yummy recipe from this awesome cookbook - although my copy is the one I used when I was their age.