Because I'm having fun with such things at the moment, an old-school geek link for you.
Here's
how to build a cantenna for your wireless network. Famously first done with a Pringles can, but you can apparently get better results with different tins. Costs around $5-10 to build, yet buying one costs about $150. Nice!
Unfortunately, no word on how to build a cantina yet. :)