An anonymous reader sent us a link to these neat speakers made from used cans. Oddly enough they convey a rather chic sense of style. The instructions are written in german - but you can pretty much infer the necessary steps from the supplied images. I'm guessing they may sound a bit "tinny"? - Link
Related:
Fold-Up Speakers - Link.
From the pages of MAKE:
Make - Volume 12 - Styrofoam Plate Speaker (DIY: Music) (Page 131) - Link.