The Wi-Fi Predator is like a Wi-Fi swiping sniper rifle, capturing distant ethereal Wi-Fi signals for your internets. Basically it tosses a directional antenna with the relatively easy (and awesome) DD-WRT router firmware hack, which will let you boost your router's power to 200dB and set it to feed off other wireless signals. The instructions look lengthy and scary, but they won't take you more than an hour or so.
After you have the router configured and the Predator assembled, all you've gotta do is point it in the general direction you plan to steal signals from (obligatory disclaimer which could be illegal in your locale), and it'll automatically grab the strongest one around that can connect to the internet. Overall, pretty neat hack, and useful (and totally legal) if you need internet in, um, your tree house. [I-Hacked via BBG]