Argument number 1: Is the jack-o-lantern evil or is it saintly? This one clearly comes from folks who have too much time on their hands and not enough things to do with it. The "evil"-sayers point out that the origin of the custom of putting lights in carved vegetables was with the "pagan" pre-Christian Druids in northern (i.e., not Mediterranean) Celtic lands. They have a point. Before and during Druidic ceremonies the hooded practitioners would hang a carved and lighted turnip around their necks to serve as a "spirit guide" to get them to and safely through the spiritually and physically dangerous procedures, which sometimes included human sacrifice. It's hard to argue that the human-sacrifice part was not evil.
The contrary argument is that the carved-lit-turnip regimen was safely transformed into non-pagan (i.e., Christian) custom with its own associated folklore. By the eighth century all the Druids had been eliminated or co-opted and new legends explained "Jack of the lantern". There are several versions, but they seem to be inter-related. The basic story goes like this:
Whatever the jack-o-lantern's origin, it is clear that the Christianized version of the story is what was brought to United States by the Irish peasants who fled the "Great Hunger", the potato famine of the 1840s. In the Americas, the Irish found a native and more likely vegetable to carve and light, the Cucurbita pepo, commonly called pumpkin. Pumpkin carving spread from Irish enclaves and is now a world-wide phenomenon -- especially around Halloween, because that's when they ripen in Northern Hemisphere temperate areas. An Internet starting point for the lore and lots of other pumpkin info is at http://rats2u.com/halloween/halloween_jackolantern.htm.
Argument number 2 is about whether the giant vegetables that are now competitively grown in the US and elsewhere are pumpkins or if they really are "winter squash". This may sound as esoteric as the good vs. evil argument above, but the pumpkin vs. squash case involves money and sometimes even lawyers, so it must be important. It's all about whether the "Atlantic Giant" variety, Cucurbita maxima, is eligible to be entered in local "biggest pumpkin" contests. Local rule-making groups have gone both ways and there have been lawsuits. Because the cases are local, none of them seem to have made it into the Federal Court system, but there is bound to be some sharp lawyer out there who will find a Cucurbita maxima that crossed state boundaries to get to a contest in some border-straddling town. Then they can make a "Federal Case". For learned opinion about the place of the varieties of Cucurbitae in the grand scheme of things, go to http://www.cals.ncsu.edu/sustainable/peet/profiles/c16squas.html.
And then there are several "half" arguments. When you carve your Cucurbita, should you cut all the way through the shell in the "traditional" manner, or is it all right to sculpt the surface of the shell cutting away just the hard rind and leaving a layer of translucent flesh to glow softly in the darkness? Should you cut off the top or perhaps the bottom to take out the seeds and slimy threads? Can you use an electric light, or must it be a candle? Is it OK to carve a long pumpkin horizontally? Must you do the "ecologically correct" things with the remains, or can you just lob them into the nearest Dumpster?
Pumpkins are often the last things harvested, and the folks obviously have a lot more time on their hands for arguing when all the hard work is done.
Eat your Cucurbita! Almost all parts of cucurbita plants are edible and extremely healthful. The fruits -- pumpkins and squashes - are well known and are great sources of anti-oxidants. Those with orange and yellow flesh get their color from beta-carotene, one of the plant carotenoids that are converted into vitamin A in the body, and they may reduce risk of some cancers, heart attack, and some aging processes. (You can also rub orange squashes directly on your skin both for the benefits of their beta-carotene and as a natural exfoliant.) The flowers are also loaded with beta-carotene and can be eaten raw in salads or cooked. The leaves have lots of iron and other minerals and vitamins and are good raw (smaller new leaves) or cooked (mature leaves). Stems can be chopped and boiled with other veggies and provide cleansing vegetable fiber. Those slimy thready things that the seeds rest in make nutritious soup. The seeds are best of all, dried and eaten raw or baked (but don't add too much salt!), and are loaded with the right kinds of oils, protein, and vitamins. "Carving pumpkins" are generally more coarse and woody than the best "eating" varieties -- the carvers are bred to last on your front porch. Orange winter squash make the best "pumpkin" pies because their flesh is softer and smoother, but the coarser varieties do a better job of scouring your lower gut as they pass through. Watermelons, other melons, and cucumbers are cousins of the cucurbitae and, while they are certainly healthy, they don't have as much nutritional value.
For more info, go to http://www.urbanext.uiuc.edu/pumpkins/nutrition.html
or to the "The Cucurbit Network" at http://www.cucurbit.org/
P.S.: Although all of the cucurbitae have Latin names, an ancient Roman wouldnít know a pumpkin if it fell from the sky and bonked him or her on the head. All pumpkin cucurbitae varieties are from the New World, and that's why those ancient Celts were reduced to using turnips for their jack-O-lanterns. After Columbus, Italians and other Mediterranean types quickly brought the pumpkin into their gustatory repertoires, just as they did with tomatoes, peppers, potatoes (think gnocchi), some bean varieties and American corn (maize), which never really caught on as a cooked vegetable, but is used extensively as a grain (all those polentas).
P.S.2: It's thought that the old Romans called their squash varieties "cucurbitae" because of their spreading growth pattern: they "ran along" the ground. "Cucurrere" meant to "run along" or "run away" in Latin. There was even an ancient Roman joke playing on Julius Caesar's famous aphorism, "Veni. Vidi. Vici." ("He came. He saw. He Conquered."). Less valiant successors of Caesar were often accused of uttering "Veni. Vidi. Cucurri." -- "He came. He saw. He ran." (Caesar's aphorisms were not at all appreciated in his own time. He was almost universally thought to be a very lucky but not a very good general -- he wasted a goodly number of his own troops -- with a very large ego and a big staff of press agents and spin artists. It all caught up with him on the Ides of March in 44 BC. The world's foremost authority on Latin aphorisms is Arto Kivimaki, a Finn. (Finland is a hotbed of Latin language study.) Go to: http://www.helsinki.fi/lehdet/uh/41997d.html.