Submarine races?

It sounds like a joke or an excuse kids might use to grab some, um, private time at the beach. ("We're off to watch the submarine races...")

But the International Submarine Races are real and --- here's the thing --- these are human-powered submarines!

Each team must develop a one or two-person "Wet" submarine. Two-person subs must have one person providing the propulsion and the other navigating and steering. Both crew members breathe SCUBA from the air supply carried aboard. Each sub is unique, designed from "scratch," and relies upon novel techniques for propulsion and guidance.

Some tests are done in open ocean; others in controlled environments borrowed from the Navy:

The 10th ISR just completed. Photos and more on this year's, and past, races:
http://www.isrsubrace.org/index.cfm