Higher education in the US is going into hibernation.
With budgets tight, energy prices high and demand for conservation growing, universities and colleges are shutting down for winter more tightly than ever before.
Thermostats are being lowered, lights turned off and services suspended, leaving many campuses dark, cold and empty but for lonely security guards.
In some places where financial problems have been particularly severe, employees will be furloughed without pay or required to use annual leave - at a time when students will not be around to notice - while in others, they will enjoy fully paid leave.
The University of Minnesota campus in frosty Minneapolis-St Paul will shut down most of its 170 buildings during the winter break, contributing $160,000 (£102,000) towards a $2 million saving the cash-strapped institution is seeking to make from its annual energy bill.
Some 8,200 university workers face three-day unpaid furloughs, while other Minnesota faculty and staff have already had their pay cut by 1 per cent.
In neighbouring Wisconsin, all public university employees are being required to take eight unpaid furlough days this year, one of them on 30 December. The other mandatory furloughs are scheduled during holiday periods, too.
"These days were chosen to avoid interfering with any instruction and to minimise disruption to the university community," said Dennis Chaptman, a spokesman for the University of Wisconsin-Madison.
Bah humbug, said John Curtis, director of research and public policy at the American Association of University Professors.
He added that the timing was intended to hide the unpaid furloughs and the retrenchment underpinning them: "There are a number of faculty who feel that no one is noticing the impact of these budget cuts."
At the University of Nevada, Las Vegas, the campus will be shut from Christmas to New Year's Day, during which time employees will be required to use their annual leave.
An internal survey shows that while a few faculty do not like being told when to take their holiday, 88 per cent are in favour of the idea.
Other schools in warmer latitudes are also shutting up shop.
Stanford University, near San Francisco, has launched its Turn Off for the Break campaign, in which departments that empty their classrooms, laboratories and offices over Christmas will be entered into a raffle for prizes, including a barbecue. The goal is to temporarily shut down 191 of the campus' 255 buildings.
The University of Pennsylvania also has made a contest of saving money during the winter break. Its Power Down Challenge will pit student halls against each other to see which can unplug the largest number of appliances before the holidays and reduce energy use by the greatest margin between 23 December and 3 January.
Turning off all the computers in an office with 300 employees would save $700 in that period - and Penn has a workforce of more than 16,300. "While many of us depart for the holiday, the appliances we use every day remain behind, continuing to draw energy," said Dan Garofalo, Penn's environmental sustainability coordinator.
At nearby Pennsylvania State University, the campus has been closed, thermostats have been reduced to 13 degrees Celsius and employees have been given seven paid days off. The energy conservation measures are expected to save more than $250,000.
Some universities will shut down for even longer periods.
Western Kentucky University closed on 18 December and will only reopen 17 days later.
"A lot of universities hadn't thought about doing this before - taking advantage of that time to make a conscious effort to save money," said Western Kentucky spokesman Bob Skipper.
The institution found that some of its buildings were so old that the lights did not have off switches. They have since been installed.
Other universities will use the holidays for charitable pursuits. At Unity College in the cold northeastern state of Maine, employees collected unwanted office and school supplies and clothing to reuse or donate once the students left. They will not return until 10 January.
As for the staff who maintain campus grounds and buildings, they are left without much to do during the break. Many will use the time to attend their annual national convention, this year held in Florida, the "Sunshine State".