Recently I found a 2-speed 'eggbeater' style hand cranked drill at a pawn shop, a Stanley no 742. We have a similar single speed drill that was a family heirloom, but lacking the lower gear it's difficult to use for higher torque applications. Changing gears on the 2-speed is accomplished by removing the entire crank and placing it in a different position. The tool is extremely heavy but it still works and I thought it was an interesting piece of history. In searching for information on the new drill I came across a page on hand cranked drill presses which looks interesting: http://www.beautifuliron.com/thepost.htm
In the last little while I have made a few visits to the shop of a family friend who is a retired sheet metal worker and I was surprised to see how many of the heaviest pieces of machinery are operated by muscle power alone. It's got me thinking that it's handy to have tools that will work when the power is out, which may well happen for extended periods increasingly in the future. The antique tools are built for extreme durability, but I guess there are probably some more recent versions that would weigh less without sacrificing longevity. For lighter work a push drill would be handy to have, but I have not come across one in my travels.
Aside from tools that were designed for use with human power in the first place, there's also adapting normally motorized tools to be powered by pedal/bicycle power for example. There is a book called "The Human Powered Home" that someone had from the library that had information on many such tools, from grinders to food blenders.