The hurdy-gurdy is an ancient stringed instrument that makes sound with a turning rosined wheel. It has both drone strings and melody strings that are shortened by keys. Some hurdy-gurdies also have one or more buzzing bridges.
The player usually turns the wheel with his right hand and plays the melody by pressing the keys with his left.
Some people claim that it sounds something like a bagpipe. Of course, its not a wind instrument but it is characterised by persistent drones that remind one of a bagpipe. The sound is quite medieval. It's well worth checking out the following links, especially if you're not familiar with this intriguing instrument.
Melissa the Loud
If you would like to try a free software version of the hurdy-gurdy, visit Soundbytes