These kinds of very simple logging applications might be good for the super-low power, inexpensive TI Launchpad MSP430 microcontroller boards.

Ive never used one of these boards, though. They seem to be very good for a certain kind of thing, very low power operation.. For example, I think I have seen devices built with these chips run off of ambient radio waves - no batteries. Free energy.

Can't beat the price. One could build a device that could be able to run off of wind power or stored inertial power alone.

That would be pretty cool. They are having a contest for interesting ideas of things to do with their boards. Ive never done anything with the MSP430 but I can say that TI are a very user-friendly company to deal with. Unlike many big companies they are extremely helpful at answering questions. They will also (depending on what it is) often supply a potential customer free samples of most of their products.

This is their web site.

http://www.ti.com/launchpad