I agree with radnab. IF you have the full day & are renting a car, go see Banff & Canmore...........you won't be disappointed.

Calgary has good ethnic food, but its buried in the suburbs and far away from downtown. If you chose to stay in town, forget about the options above & consider instead:
- afternoon tea/stay? at the Palliser (recommended the Gold Floor, now renovated);
- go for a walk at/near Bow River. There are lots of young people who live in YYC, and they are big on outdoor activities! e.g.:
http://calgarysbestwalks.ca/index.php/book-events/
- visit the Olympic Park, home of the 1988 Winter Olympics.