I was once a vegetarian and found myself facing a very meaty Thanksgiving with relatives who tended to cook all vegetables with chunks of pork. Nowadays that sounds delicious, but I would still happily eat any variation of the following.
This works as a main or side dish, can be partially made ahead of time, and can be made vegan- or vegetarian-style (or you can fill it full of meat).
It makes a totally cute centerpiece and topic of conversation, and then you get to destroy it by slicing off pieces of the pumpkin's walls as you serve up its delicious innards.
The short version: cook up a bunch of wild rice and veggies, spiced to your liking. Hollow out a pumpkin, fill with rice mixture, cook until pumpkin is done through, eat it.
I don't have a proper recipe for this, but here are some general guidelines that worked for me:
For reasons of texture and flavor, you want a sugar pumpkin, which may also be called a pie pumpkin. These are the medium-sized ones, not the wee decorative useless ones nor the huge ones meant for jack-o-lanterns. They're usually about 8-10 inches across. If possible, pick one that's wide rather than tall; this will be easier to serve from. And make sure it has a good grabbable stem, which will function as a lid handle.
The procedure that worked best for me was to cook up some wild rice, separately sautee a bunch of vegetables (I used green beans, corn, carrots, celery, and onions), then fill the pumpkin with these and finish it in the oven.
I also added a bit of cooked soy-based beef crumble approximation, which can be weird but was excellent in this context. These days I'd either use actual ground beef, or skip it altogether. If you're going meat-style, I can't imagine bacon would be out of place. You could probably get crazy with some dried cranberries and toasted pecans in there, too.
It's probably best to take the rice off the heat when it's not quite done - it won't really continue to cook inside the pumpkin, but will soak up more liquid. Also, if using wild rice, make sure you budget enough time, as it takes forever.
Taste the rice + stuff before it goes into the pumpkin!! This is your last chance to season it. In particular, make sure it has enough salt, as you're going to be serving this with slices of unseasoned pumpkin. This works fine if the contents of the pumpkin are appropriately seasoned (sage is great in this).
While the rice, etc. are cooking, deal with the pumpkin. Rinse the exterior and scrub off anything gross (the oven will sterilize it, but they do grow in mud). Cut a lid out of the top in the classic jack-o-lantern style. Do yourself a favor and make the shape of this lid large and somewhat irregular! This will keep you from going crazy trying to fit that piece back in, later.
Scrape out the seeds and disgusting business inside. Be thorough. Shine a flashlight in there if you have to.
You can wait until this point to fill the raw pumpkin with the rice stuff and bake it; you can also give your pumpkin a head start, cooking it partway before the rice mixture is done.
Pumpkins are forgiving; if you need to cook it for a while, then take it out of the oven and finish cooking it later, that will work fine, provided you keep its lid on and don't let it dry out. (drying out? spritz with water)
You'll thank yourself if you bake the pumpkin, filled or empty, in a roasting pan, or at least on a cookie sheet with a rim. By the time it's done all the way through, it may be a little leaky.
Cooking time varies, but should be around an hour at 350 F (175 C) on your oven's bottom rack. It's done when easily pierced with a knife.