Today's information comes from the trusty people at:
http://en.wikipedia.org/wiki/Pumpkin and another cool site:
In Ireland (and many other countries which have their variations) the carved out pumpkin with candle inside is meant to represent the Ignus Fatuus or Fool's fire. Stemming from the wonderful folklore story of Will o' the Wisp. There's a great write up on this on http://irelandsown.net/willothewisps.html, a story that is well known to many here in Ireland, though we never had pumpkins - we used turnips. Believe me carving and hollowing out a turnip, is not the most fun, at least pumpkins are soft!
Anyway back to the humble pumpkin. It is a squash-type vegetable but there are some differences between the two. To get technical the squash has a softer, rounder, flared stem as opposed to the pumpkins hard,rigid, prickly, square-ish stem. There's so little in it at times, that the names are interchangeable. They're both in the Cucurbita family (which also contains cucumbers). A pumpkin can be many varying shapes, textures and colours, we usually think of them as orange but blue, grey, green, white and red are also found, some are a mixture of the above like a beautiful painting that has run in the rain.
Most parts of the pumpkins can be eaten, the flowers (of which there are male and female on the same plant), the seeds and of course that gorgeous flesh - the orange-ness of which is a perfect indicator of it's antioxidant properties and presence of Vitamin C. Again, the science part ; this colouring is due to lutein, aplha-carotene and beta-catotene which convert to Vitamin A in the body.
But did you know that the seeds are also extremely good for you not to mention, very tasty indeed, especially when roasted (though this lessens the benefits a little). Apart from the cartoenoids, they also contain healthy fats and zinc which is great for bone strength and protein and fibre too. In its oil form (available from health food shops), it has been known to ease the pain of arthritis due to its anti-inflammatory properties, being a humble seed, there are no nasty side effects. Hoorah.
But never mind all that - basically it tastes great, it's good for you and there are hardly any calories (it's 90% water) or fat. So eat as much as you want - yummy.
I give you Pumpkins Ladies and Gentlemen. Grow, harvest, eat, enjoy!