I've never done this before but have heard its fun - come and give it a try with me! Remember that you'll need a Grouse Mountain pass to ride up and back down the Skyride, or if not, a single adult return trip cost is $39.95 (yet only $99 for an annual pass - a very good deal!)
The following description is taken from the Grouse Mountain website:
The Snowshoe Grind
Grouse Mountain has translated the intensity and accomplishment of the Grouse Grind into a winter experience – the Snowshoe Grind. Located mountaintop, the Snowshoe Grind promises to challenge. Starting at the relocated Grouse Grind timer, outside the Chalet adjacent the Skyride ramp and just southwest of the skate pond, the Snowshoe Grind is the perfect way to start Grouse Grind hiking season fit and strong, while embracing a snowy winter landscape.