here in Prague, it is a very traditional system...even the profs regularly take overnight in-house call. i think it really varies country to country....
the last time i was on call i asked my resident what his worst strech of hours was. it started with call monday, off tuesday, call wednesday, off thursday, call fri-monday, off tuesday...repeat x 3 weeks. he had about 25-30 hours OFF a week for 3 weeks. that is nuts!!! and this was 2 years ago...bad luck for him, but similar schedules still happen to the unlucky interns fairly regularly.