I've just finished making some pendulums for an order and find them quite fascinating.
Dowsers use them to find out all different stuff, but as a woodworker I think they're cool.
You can get one HERE
These ones are made from some very old beech found up here in the Highlands. The spalted ones are a long, thin type of pendulum known as "Radionic" which is supposed to be particularly good.
Some people get into dowsing using rods whilst others use a pendulum - it's whatever works for you.