I do nunchucks, have done for years. There is basically 2 different styles of using them, one is doing crazy stuff like spinning them round your hands, wrists, neck, arms, legs etc, which once you've done them for a while, you can get really fast at doing it.
.... and it also looks cool as fuck when they become a continual spinning mass flying around your body, and feels great when you get into a flow with them.
The second style is to learn the combat techniques, using longer, heavier wooden (or heavy metal) chucks. Combat techniques are much slower, powerful moves and will cause you serious damage when you fuck up. Learning the grips and momentum of the nun chuck is key here.
They can be absolutely devastating weapons, especially when using the simplest of moves. If you hit somone full force, full swing with a heavy pair of chucks you will easily break an arm, wrist or leg etc. If you were to just swing them as hard as you could off someones head, cracking a skull and killing someone would be quite easy, and even if an attack is blocked, you're still going to seriously damage a limb.
Of course, using them as a weapon isnt that practical, it's not as if you can carry them around with you for self defence. You can get telescopic ones that are easier to carry, but they suck.
All in all, they are great fun, build up your muscle tone in your arms and upper torso, and increase your dexterity. Mastering 2 at a time is much harder, but looks and feels cool as hell when you eventually get it down.
