There's a few previous threads about this if you search. Lots of good info in those.
I've eaten at over a dozen different sushi restaurants in Calgary, and by far the best (IMO) is Globefish. They have two locations, one in Kensington and one in Marda Loop. Judging from the autographed photos on the wall, lots of Flames players like Globefish too.
http://www.globefish.ca/