The grooming schedule for the 2015-2016 season is available over on the Mountain Trails Grooming Association site.
If you are interested in riding along on the groomer during one of their runs, email MTGA at firstname.lastname@example.org. It can be a long day and the groomer isn't a speedy ride, but it is fun way to experience a day in the life of a grooming machine operator. Don't forget to bring your lunch and camera. You never know what you might see as you are crawling along.