You might want to print this page for reference, but beware of occasional changes.
Mind the Support Hours
Periods outside these times are used for appointments, support tasks requiring longer examination, and for infrastructure maintenance.
Server Maintenance Hours
Server Maintenance Hours are each Thursday, from 07:00-08:00.
During these times, server operation is unreliable. You should expect unavailable servers and sudden downtimes of services without prior explicit announcement.
See here for details.
Support is available only on regular working days. There is no IT support on weekends or on public holidays.
You can find a lot more information about efficiently employing IT support in Contacting IT-Support for Staff. Also, the priority system used is described, the tasks of IRC-IT, and alternative contacts are given.
It will be easier and faster to answer your questions, if you keep a few things in mind upon requesting information, including being specific. Please see the interesting hints on asking questions at Geek to Live: The art of asking or Web Worker Daily: How to Prevent Tech Support Nightmares. Also, employing How To Ask Questions The Smart Way might help to get faster and more helpful answers.