I don't know anything about, or have much interest in, high-frequency trading.

But some of the technology behind it is fascinating. This past summer the Sniper in Mahwah blog published a four part series investigating the use of shortwave radio as a low latency link in high-frequency trading. I’d call it the best piece of hacker-tourism since Mother Earth Mother Board, but I think it’s probably the only piece of hacker-tourism since Mother Earth Mother Board. It doesn’t have much competition.