We made use out of some of our old boxes and lights leftover from Christmas today and made a cardboard box fort. After we taped it together I used a knife to put holes in the top to push Christmas lights through.
I let the girls decorate the walls and ceiling with markers, stickers and some colored flower cut outs I had leftover from another project. They LOVED decorating the walls.
Now that it's done, I haven't been able to get them out of it! They have been playing with their Christmas toys and as I am typing this are watching a movie in preparation to sleep under the twinkling lights all night long.