If it rains in, you close the window. But what if your room is too hot or cold? Get students involved in trying to moderate temperature extremes based on their level of competence and how you can integrate the project into existing weather or science lessons.
For something different, try making Christmas ornaments out of recycled materials. Brainstorm with your art teacher how that might be accomplished in an aesthetically pleasing way, or tackle it on your own with bits of plastic, paper, aluminum foil, string, wire, etc.