Mike,
There are several gliding clubs in Alberta (see the
Alberta Soaring Council website, but you are coming at the wrong time of the year.
Gliding finishes when the snow comes - typically in October and doesn't start again until March/April.
The closest club to Calgary is Cu Nim at Black Diamond.
If you want to go flying in December (provided it is not too cold - not less than -15C should be OK
), I would recommend a mountain checkout and if you contact one of the operators at Calgary International (
Morgan Air or
Calgary Flight Training Centre), you'll get to fly off the same 13,000 ft runway that you arrived on from the UK!
PM me if you want more details