A popular hacking past time among rural Minnesota dorks, is war-driving. Hackers actually leave the house and go driving around neighborhood looking for wireless (802.11b) networks.
A tool that greatly aids their search is a Pringles can, seriously. Apparently with a few household items (simple how-to and shopping list) you can boost your easily boost your signal by 15%, and a lot more with a little know how. Another site has an antenna shootout that compares different kinds of cans to see which produces the most signal gain.
This has been around for a while, but I thought I would mention it for practical reasons. Like, for example, if you want to be able to access your wireless network from your garage you could place one of these wave guides out there. Or if your walls use the old thick sheet-rock and your having trouble getting signal in some parts of your house. Oh hell, mostly it’s just for stealing your neighbors bandwidth, so watch for renegade dorks with Chunky Soup or Pringles cans aimed at your front porch.