A great indoor activity for any time of year is shaving cream "snow." Trip loved this activity because he got to take off his shirt. And then, since his shirt was off, he wanted all of his clothes off! Considering the potential for a big mess, I figured he might as well be naked.
I had Trip choose between playing with animals and cars. He chose cars, so while he found a few cars, I sprayed some shaving cream on a cookie sheet. As soon as he came back to the table, the cars got very "snowy."
Right about this point, he got very upset that the car was "all mess" and wanted me to clean it.
With a clean car in hand, it was time to get his fingers in it.
And then some of the shaving cream ended up on his tummy.
Shortly thereafter, Trip was ready for something else, so he played with water in the sink for a while (a new favorite pastime).
Meanwhile, I mixed up some "snow" paint (which could double nicely as "cloud" paint as well) with the shaving cream left on the cookie sheet. I discovered from this pin that equal parts shaving cream and white glue makes a fun paint that dries puffy. Trip was too busy playing in the water to care about painting, so I started making him some snowy letters. I ended up having enough shaving cream to make the whole alphabet.
The paint doesn't dry quite as puffy as it starts out, but it has a really nice silky feel to it and does retain some dimensionality. In the future, these letters will be great for Trip to practice tracing out letters by following along the lines with his fingers.