Okay here is my theory for what its worth. Feel free to poke holes
Calgary will bid to be the host for the 2026 Winter Olympics (or World Cup)
AND
A new, world class, multi-sport stadium will be built, capable of housing NHL, CFL, NLL and MLS franchises along with perhaps a new track n' field area and maybe a Velodrome for cyclists etc. The new stadium will also incorporate all sorts of retail, bars and resto's along with high density housing with easy access via train. It'll be ready a few years before 2026....2018-2020 perhaps... Part of Nenshi's legacy.
Location
Of all the potential locations discussed so far, I really like the west village area, next to the river (near the science centre, Greyhound etc.) creating an all inclusive recreational zone in Calgary's downtown, similar to Melbourne Australia (photo) - a world class sports town.
^^^Imagine this is a photo of Calgary taken from the Crowchild/Bow Trail overpass.