Google announced they would be sending attendees of Google I/O a free Android phone in the mail before the conference -- free phones for the second year in a row. Americans were assigned Motorola Droid phones, and Canadians were given Nexus One's.
It turns out they sent the version of the Nexus One to Canadians that doesn't work on the Rogers 3G network -- Canada's largest GSM carrier. Instead, Canadians are required to use 2G or Edge networks on their new phones.
Even though it's less than ideal, it would be silly to look a gift horse like this in the mouth. The phone isn't ideal, but it gets the job done.