I found, quite by (lucky, eye-poppingly amazing) accident, a how-to video by Roben-Marie Smith, showing how she makes envelopes out of old file folders. Guess who has old file folders (I DO) so I thought I would try a couple of these. They were so much fun that now I want to make about 25 more. The only snag I ran into is that my file folders are pretty cheap ones - I don't remember where I got them from but they're at least years old; and although at first glance they look perfect for this project... well, they're not square. So I had to do some fancy folding and cutting to get the edges to all line up. At first I thought I must be doing something wrong, but I guess my only mistake was buying el cheapo folders in the first place. (The $20 sewing machine is a whole other story...)
Anyway, who needs files? These are way more fun, don't you agree?