In an educational IT setting, where tens of thousands of students may be dependent upon access to thousands of identically configured workstations anytime, day or night, the challenge to keep those workstations current and up to date can be daunting.
Unlike Summer break, when student populations are down dramatically and there is plenty of time to plan for upgrades, Christmas break leaves little time to plan and even less time to implement sweeping changes.
First and foremost, determine weeks in advance what changes REALLY need to be made between mid-December, when Fall classes are out, and mid-January, when Spring classes begin.
If you haven't already, adopt and publish policies which make it clear to faculty that changes to existing applications which are not security-related are not permitted during this time of year, and enforce that policy to the greatest extent possible. If need be, let your boss make the call -- it's better than getting blamed if you decide on your own to deviate from policy to accommodate an intransigent faculty member and things go south.
Version changes can wreak havoc on students and faculty returning in the Spring -- even when such upgrades include only minor changes in 'look and feel'. Add in unanticipated file format changes and large numbers of students may find themselves suddenly unable to work on their assignments on their personally-owned computers. (For instance, installing Office 2007 this December is NOT a good idea. On the other hand, installing the Compatibility Pack for the 2007 Office System might be a good idea since your students may very well upgrade to Office 2007 on their own computers during the Spring semester.
Plan, plan, plan. No one wants to miss Christmas dinner because a site upgrade goes bad. Know the time-off schedules of your IT staff well in advance of the break. Balance your work schedules to permit all of your staff to enjoy the holidays and still be available when you need them most, that last week before the students return. Something ALWAYS comes up at the last minute!
For Heavens sake, whatever you do, don't plan on any kind of an OS upgrade between semesters. You may be chomping at the bit to get Vista (or your favorite new Linux distribution) on your machines at work but believe me, your users will not be so happy when you change their production computing environment on them without ample warning. (What is ample warning? Months!)
Before you make any widespread changes, make them on a few machines and evaluate the possible consequences. (Ideally, you should have done this before now in your testbed environment.) There are always unintended consequences to any change in a production computing setting. You cannot anticipate them all but, with careful planning, you can minimize their impact.
Oh, and enjoy the holidays!