What is a rutabaga anyway?

Monday was a first for me - I bought a rutabaga.  Do you even know what one looks like?  I kind of did - like some turnip thing right?  But I've never bought one or cooked with one.  So I was browsing around online trying to make a menu for the week, and I found a recipe for Farmhouse Chowder.

 Looks yummy right?  But it called for rutabagas.  So I bravely went to my grocery store and picked one up.  The cashier actually didn't know what it was either.  So with all of the mystery surrounding the rutabaga I was curious -does it even have any nutritional value?
Here's what I found:

• It is related to cabbage, cauliflower, broccoli, turnips, etc.
• Excellent source of vitamin C, potassium, and vitamin A
• Harvested in late summer and early fall

So it does contain some vitamins and fiber.  It's going in the soup tonight.  I think the soup will be delicious - I'll let you know.  I'm curious - have any of you cooked a rutabaga?