Some calendars are simply too beautifull, to be discarted after only one month / year... This was the case with this wonderfull calendar full of wonderfull illustrations by Die Gestalten Verlag in Berlin... So I thought about, what I could do with the sheets - and decided, that I needed some new envelopes (yes I still use snail mail ;-).
Step 1: What U need
What you need is - obviously - the calendar sheets; an old envelope, that you can cut open (I used a knife), a pencil, glue and a pair of scissors. That's it - pretty simple.
Step 2: Go to Work
Now, you use the cut-open-envelope as a pattern. Draw the shape of the flat envelope on your calendar-sheet and cut it out. Tuck the four flaps so that you get the envelope - and paste three of them together in order to get the envelope. That's it - you're done...