Calgary in January can be 50 to 60 degrees, or it can be zero (first one, then the other) so making rigid plans a month and a half away can be difficult.

The Calgary Zoo is one of the best anywhere and you could kill an entire day there. I would personally avoid the area around the river through downtown there are just too many vagrants and some of them are severely disturbed. For the river I would head to Edworthy Park which is west of downtown for good pictures I would head to SAIT which is just a quick train ride from downtown.