Jim, great news! Here is the info....
You cannot register on-line, HOWEVER, you can register in-person! If you are there Thursday BEFORE closing time of the Registration Booth (4:00 pm) you can get registered. If you are early enough before 4:00, you might opt for the 3-day pass at $25. If you are close to 4:00, I would suggest coming back on Friday morning and registering for the day ($10) but you might be able to register for both remaining days at the time (Friday and Saturday for $20).
HOWEVER, I do not have the detail about maybe registering close to 4:00 on Thursday for Friday and Saturday entry. Where these details become important is whether or not you want to play in the Thursday Night poker tourney and I am a bit fuzzy on that detail. You should send an email to the Convention Chairpersons at: Convention@CCGTCC.com.
But generally speaking, you cannot register on-line, but you can certainly do it in-person!
Jim Follis