This is a good upcycle as well as a good technique for growing your own veggies when the weather may still be a bit cold -- Cold frame window. Helps you grow vegetables and plants earlier at spring. Good re-use for those old windows!
Green Greenhouse-A smart little greenhouse made from old windows are easily set up to house wall. Here seedlings grow large before they are planted out. Old windows and doors are found at flea markets and recycling stations
Cutest little garden shed/studio made from all recycled doors, windows, trim.-- I think my Garden Shed was supposed to look like this, but it looks more like a house now--I had too many doors and windows to put in it.