It is 5F/-15C here in Minneapolis. It is definitely too cold for me to go outside with the kiddos!
While Soleil napped (ok, not really, but I left her in her crib for mandatory "quiet time"....)
I set up 2 tents in our family room.
I pulled out every book that was camping, outdoor, or bug related.
I found every compass, flashlight, telescope, lanyard thingy we had.
I pulled out every squishy creature and all the stuffed animals.
I pulled out the sleeping bags and all the pillow in the casa.
The last step? I took the kids to the library after school and came home with a bag of fresh books for each of them.
This resulted in hours of play. Heck, if you come over right now, it is still set up. Tate begged to keep it up permanently. This isn't exactly a project that you make to keep, but it was creative and fun!