I can no longer surprise them. Every class opens, in the faint light of early morning, with a partial drawing-down of blinds, while the projector blinks and the slides flicker, and my familiar, aged, throaty, cynical drawl defies my students to stay awake.
The only entertainment, lately, has come from my hacking cough or my loud rage against the intractable classroom technology. This morning, however, was different. I had to turn over a few minutes at the start of my class of freshmen and sophomores to a charming final-year student who exhorted them to think about enrolling as teachers.
The Teach for America (TFA) programme, which was the subject of today's early-morning diversion, recruits university students for a form of paid national service, sending them, after a few weeks of basic training, into some of the nation's most underprivileged classrooms for two years immediately after graduation.
"Educational inequality," says the programme's slogan, "is our nation's greatest injustice." This is debatable in a country that practises unjust warfare, complicity in torture, rationally indefensible levels of imprisonment, sporadic rites of capital punishment, alarmingly irresponsible levels of abortion, and shameful neglect or denial of the rights of people accused of terrorism.
But the school system is a standing disgrace in a country that has always made a fetish of equality of opportunity. Local school boards run maintained schools. If you live in a poor neighbourhood, you are condemned to a resource-starved school. This is not a postcode lottery: the odds are stacked, the numbers loaded and the outcome fixed.
The children of the underclass cannot work their way out of subjection. Fifty-eight per cent of US citizens have some experience of further or higher education. In the schools that TFA targets, the average is only 10 per cent.
Since the programme started in 1990, it has put 20,000 young teachers into the field. They work in hurricane-wrecked schools in Greater New Orleans - collections of shacks, without access roads, in an area where, even before Katrina hit, two thirds of the schools were classed as "unacceptable" - or in the economically devastated desert suburbs of Las Vegas, in a school where 55 children are officially homeless.
Amazingly, about half the graduates stay in teaching when the programme is over, even though employers and graduate schools see TFA as a hot recruitment ground for their own purposes.
Naturally, in the US this is not a government programme (although the Department of Education is now among the big donors). A Princeton University undergraduate started it and raised the first $2.5 million (£1.6 million) herself. On the face of it, this looks like an initiative with no losers.
When my student has finished exhorting the class, no one has any questions. So I weigh in.
"Isn't this just another typical instance of a widespread American vice - amateur philanthropy relieving the state of its responsibility for the welfare of the poor?"
No, I'm firmly told. The programme's aim is not just to plug the wealth gap but also to change the country. In the long run, TFA will recraft national policy by building up a critical mass of dedicated, influential teachers, experienced opinion-formers, committed policymakers and socially committed entrepreneurs from among TFA corps alumni and the students they help to raise from deprivation.
OK. "But isn't the whole project an apology for real reform - making up for a shortage of real teachers by cramming the ranks with raw, ill-trained, under-prepared labour, with none of the discipline that comes from commitment to a teaching career?"
No. Corps members are monitored in the same way as fully fledged professionals and typically score at least as highly on average. They get extra training, paid for by TFA, in every vacation.
"Do you really get recruits of quality? Isn't the programme an escape route for irresponsible students who don't have a vocation, don't know what they want to do, or simply want to postpone the evil day when they have to do a real job and repay their student loans?"
I am treated to a barrage of statistics about how well qualified TFA recruits are. They do not have to be highly gifted academically, but they do need solid records in hard work, active participation in their undergraduate courses and extracurricular activities. The character checks are searching and uncompromising.
I am worried, I say, about the kind of environments my students could end up in if they join the programme. I have almost no experience of US high schools, but I am prejudiced against them. Wherever I go I see revolting, ill-mannered, loud, ignorant high-school students.
Although college seems to have an instantly civilising, instantly maturing effect, the raw material we work with in the tertiary sector is desperately unpromising. And TFA is targeting the kinds of schools you read about in the sensationalist press, where students hang out with gangs and periodically spray their classrooms with bullets.
"None of our teachers," my student solemnly replies, "has been knifed or shot yet."