Canadians seem to be experiencing some Xbox Live issues at the moment. Xbox Canada's website is proudly telling users that while the service is "Up & Running", there might be a slight hiccup or two:
Users may experience intermittent issues with tournaments, posting statistics, matchmaking, and sending messages. Additionally Halo 3 users may experience issues joining matches or posting statistics. We are aware of the issue and are actively working towards a resolution. We apologize for any inconvenience.
But apart from that, everything else is fine!
[Xbox Canada, thanks Rajan!]