Based on press reports (Ive not yet visited/spoken with them) Glenshee are now, subject to the weather (wind limits I guess) open 7 days a week with the Cairnwell Chair for Mountain Biking.
The ski centers website currently has limited info. but as of the end of July 2010, quotes a full day (up to 4:30) adult up-lift (with bike) of £15.
In the past the center has opened on one offs like the 1997(or perhaps 98?) HG event I took photographs of, and more recently Glenshee has started limited summer opening for walkers (and of course paragliding), so the development of Mtn. Biking looks to give a boost to mountain thermal training and mountain XC flying in Scotland.
This last couple of years a number of the pilots who have/currently fly with ESP club have done (or come close to!) record distance flights and I can see use of the up-lift at Glenshee increasing this type of flying, with car sharing giving the chance of a couple of bites at the cherry in the same day!