Not the same group as you, but I immediately accepted one offer/declined the other at about 12:15 in the morning. I already had decided where I would go based on the different possibilities with SSHRC, so I didn't have to think about it. It's probable that others had the same immediate reaction, especially if (as some other posters have noted) they didn't actually apply to the schools they sent CGS apps to. Congrats, YOU GOT THE MONEY (and the pride)!
Now I'm off to finally send break up emails to the grad admins I've been begging for more time to decide for the past month and a half.
Congrats everybody! Don't lose hope if you're an alternate: remember there are only 2500 of these spread over a country with (by my semi-educated guess) over 100000 Masters students, the fact that we're among this group is an amazing accomplishment.