Update:

The RDS desktop service has now been restored to normal service.  Full service was restored on Tuesday, October 21st, 2014 at 9:45 AM.

As of 4:00 PM, Monday, October 20th:

The Remote Desktop Services, formerly called Terminal Services, are currently unavailable.
There is no access to Student Lab software listed under the Remote Desktop Services section, at this link.

http://carleton.ca/its/all-services/computers/site-licensed-software/student-lab-software-2014/

ITS is investigating the issue.