I saw a post at MetaFilter about aluminium-can folk art and decided to have a go. It turned out to be easier than I thought.
The metal is thin enough that it's trivial to cut with tin snips or even regular scissors; a ruler and a knife are good for straight lines. I used a regular Stanley knife with a segmented blade and had no problems other than the expected blunting.
Removing the top and bottom of the can without accidentally crushing it is the hard part, and even that isn't very hard. Filling the can with water and freezing it might help there, especially if using a saw.
That leaves a sheet of metal:
Once the jagged edges are taken into account, you should be able to get a usable sheet of at least 20cm by 8cm.
It's quite an anticlimax, actually, because you work with the aluminium in almost exactly the same way as with paper or cardboard; it's just harder to cut and harder to glue. (Staples work fine.) It also can't withstand repeated stress from folding, so origami is out of the question, but it's well-suited to cut-out models that don't require repeated folds. In exchange, you get something that can survive harsh conditions. If you leave the outside of the can visible, you might even get a little pop-culture cachet.
This is what I ended up with:
(And a few more.)
Nothing impressive compared to what other people have produced, but that was always a given: someone has already built an entire house.