First off, I would like to apologize if this is in the wrong section. Since this pertains to a CALCnet hub and I assume that such a hub would be on a website, I assume that I should ask my questions here.

1. What language should a CALCnet hub be scripted in? PHP?

2. How would one write a CALCnet hub?

3. Must a CALCnet hub be hosted on Cemetech, or can it exist on any site?

4. Can you, if you are building a game, host something like world terrain on the hub and have the connecting calculators download it first?

Implement however you like such that it can properly speak the protocol. The reference design (the one running on Cemetech) is implemented in Python, according to the gCnClient manual, but that same document includes the network protocol specification so it should be possible to implement your own with only that document.
The salient details are that it runs a simple packet-based protocol over TCP.

May exist anywhere, though the client defaults to Cemetech (gcn.cemetech.net IIRC). See the -s option for the client.

The hub itself is transparent, but you could build a component that hooks into the hub and appears as a calculator, I'd imagine.

For 1, 2, and 3... Understood, and thanks.

For 4... I'm not following... I need to create a whole virtual calculator on the hub, just to store map data, since I'd rather not have it stored locally if I can avoid it.

Not a whole virtual calculator, but you need something that appears to be a calculator to everything else on the network, because the hub itself is transparent so you have no way to specify that you want to communicate to it without it pretending to be a calculator.

By the way, the term for what you're talking about is a "bridge". You'd have the bridge connect to the gCn metahub (ie, gcnhub.cemetech.net) pretending to be a calculator, but offering special services. The convention is for the bridge "calculator" on a hub connected to the metahub to have an ID of all As (AAAAAAAAAA).

Ok thanks. This is related to my star trek project, btw.