To win a contest at DefCon 13, a team of geeks established an unamplified Wi-Fi connection over a distance of 125 miles, beating their previous record of 55 miles. Team PAD did it by connecting their 300mw Wi-Fi cards to satellite dishes: one computer (outside Las Vegas) used a 12-foot dish, and the other (on a mountaintop in Utah) used a 10-foot dish. (I first heard of this amazing feat on the This Week in Tech podcast.)
It is probably not a coincidence that all four members of Team PAD are ham radio operators.