Boston. The usual quiet of summer on US university campuses has been replaced by the hum of lectures, games, conversations in a Babel of languages, the sound of model rockets taking off and the tapping of computer keys.
Schools that previously lay fallow for three months of the year are now filling their coffers as well as their buildings with money-generating sports camps, study programmes, corporate training weekends and anything else that pays.
Many rent their campuses to private companies. The Estee Lauder cosmetics firm, for example, invites employees to a personal and professional-development programme at Vassar College taught, in part, by professors from the Harvard Graduate School of Business.
Schools are hesitant to specify the revenues they receive from summer programmes. But at least one, New York University, disclosed that its summer programme for international students generated more than $1 million a year (£550,000).
The hottest activities on campuses this summer are privately run programmes to help students improve their chances of university admission. Several companies lease dormitory, dining hall and classroom space from universities to run the programmes for 16 and 17-year-olds.
One takes over the campuses of the University of California, Los Angeles, and Tufts University, where students practise the SAT admission test, meet university admissions officials and undergo mock interviews.
Education Unlimited Camps caters for younger children. The Sally Ride Science Camp for girls - named after the astronaut - is held at Stanford and Berkeley universities and of Agnes Scott College in Georgia.
Students pay up to $5,970, depending on the duration of the programme.
Anxiety about passing an ever-growing number of assessment tests has created an enormous personal tutoring business, estimated at $4 billion a year, for children as young as two.
The private tutoring industry is expected to grow by 12 to 15 per cent a year, according to Eduventures, a Boston research firm that tracks the economics of private education.
The national No Child Left Behind Act makes government money available for tutoring children in schools ranked as poor.
Private tutoring companies have seized the opportunity. Kumon, a Japanese concern, has launched a programme for children aged two to four. It has 1,200 tutoring centres in the US.
Kaplan, an American-based firm that has storefront tutoring centres, has doubled the number of students in its programme for four to 16-year-olds to 82,000 a year. Of those, a fifth are under seven.
Studies have shown that high-quality tutoring can propel a student from the bottom fifth among his or her peers to the top half.