Ok, so I polished up the chat client a bit. The code still isn't ready to be released for either the client of the library, but I'll let you guys play with the executable. Keep in mind the library may change very little or quite a bit between now and an actual release. This is strictly alpha stuff right now.
http://merthsoft.com/Chat.zip
It works under mono, by the way:

This is awesome! Would you mind taking a screenshot with a window resized a bit smaller so I can frontpage-news this?

Some bug reports from testing it out on 64-bit Win7:

1) I like when shift-backspace deletes words. Here, it makes a box character
2) Entering a line and hitting enter makes a ding sound.

I also made it lag for a while when I connected, but I suspect that was my computer's fault.

Happens to me, too. There's probably a way around it, I'll check google.
I can't replicate this. (I'm also on windows 7 64-bit).

I don't suppose that your speakers are muted by any chance, are they? It sounds like the bell character; are you possibly printing it anywhere?

Oh dear. I have system sounds turned off, that's why... Hmm. I'll look into this.

For what it's worth, 0x07 is the bell character. Oh, are you stripping off the 0x00's at the end of short usernames? I don't know what C# does with \0s.

I have fixed the two bugs you mentioned, plus a couple of others that cropped up. Download now!
http://merthsoft.com/Chat.zip

Very nice, much improved. Glad one can set one's name now.

Alright, I'm releasing the code to Chat!. Moving forward I'm working on getting my TI-84+SE to talk with gCn through the direct link. Because of this, the Library is in a pretty nebulous state, but once I get how I'm actually going to be engineering this worked out, I'll release the code the CALCnet library. I'll get a commented version of the .dll out sometime this weekend, so it'll be easier to work with. For now, you can see how Chat! does it, and with this you can start making your own things!
Download: http://merthsoft.com/ChatSrc.zip
Just the Chat Client: http://merthsoft.com/Chat.zip

Edit: I updated the source to fix a bug.

Thanks for sharing! I see that Tanner at least is playing with it, hopefully hooking it up to his watch (?!). Also, I'm glad we tracked down that screen-clearing bug.

That's exactly what I'm doing >:D Or at least, looking up how to send a few bytes (complicated source o.o)

Well, best of luck, and I hope you'll be passing along your progress. Chat! v1.0 for the calculators is finally out here and on ticalc.org; I hope to post a news article about it before I go to sleep. Also, I'm switching the gCnIRCHub and (G) back to #cemetech and SAX respectively.

I've added documentation to the .dll, you can get the new version at:
http://merthsoft.com/Merthsoft.CALCnet.dll.zip

Nifty, thanks for sharing! I hope some more applications get written soon, like Obliterate or Netpong.

I forgot to include the XML documentation, so the documentation didn't actually work. Here's a new release of the solution:
http://merthsoft.com/ChatSrc.zip
and just the library:
http://merthsoft.com/Merthsoft.CALCnet.dll.zip
If you're just dropping in the library, you'll want to reload the solution.

Also, progress is being made on the USB end. I'll probably break this off into a separate topic, but here's a screenie:

You can see that I'm getting the product name, time, free RAM and ROM, and the screen image

That's great! Since it's important for gCn, can you get the calculator's ID using that?

Anything that can be gotten I can get

Awesome! Now you just need to help me figure out how to chain the CALCnet2.2 interrupt with the OS USB stuff.