Have printed images on transparencies
And then they cut out and (with a little help from some children) glued them to the window. They function a bit like sun protection (at least it dampens it a bit).
But also expands the hook for play. I've been getting a few questions, and thought I'd share the answers here. Printing on transparencies is the same as printing on plain paper. Put them in the correct tray on the printer, and do as usual. I have found the pictures through normal google searches. The tip is to use English keywords, then you will usually get more hits. Add the keywords "cartoon" or "clipart" (or equivalent), such as "cartoon town" or "clipart cars".