Two kinds of pumpkins from the UBC Food Garden's small pumpkin patch are shown in today's photographs. Absent are at least two other cultivars in the patch, 'Atlantic Giant' and a white-fleshed variety. 'Schooltime' was on Botany Photo of the Day last year, accompanied by a large set of links about pumpkins, so that's the place to go if you're looking for further reading today. I'll add one more link to the list: photographs of pumpkin cultivars via the Pumpkin Patch.
From what I've been able to gather, 'Hybrid Grey Crown' appears to have been bred in New Zealand and is now percolating slowly into other markets in the world – perhaps a false conclusion, though, as I'm drawing my conclusion from the number of online vendors from particular countries. As is sometimes the case with vegetables, it can even be difficult to determine the name — it seems to be sold as 'Hybrid Grey Crown', 'Grey Crown' or 'Grey Ghost', with the latter name only appearing on North American sites (at least one vendor adds Hybrid Grey Crown in brackets after using 'Grey Ghost'). For a relatively recent introduction, it does seem to already have a confusing set of names. Had it been up to me, I would have chosen a name that no one would have changed – perhaps 'Vampire Pallor' or 'Zombie Flesh'.
Despite resembling the outward appearance of popular Halloween critters, 'Hybrid Grey Crown' is not very suitable for carving. It is thin-skinned, thick-fleshed and small seed-cavitied. However, its sweetness and thick flesh make it excellent for food use, as it produces both quality and quantity (via Pumpkin and Winter Squash Evaluation PDF), as well as the marketing literature).