Not what you think -- a vomitorium

from www.wordsmith.org

vomitorium (vom-i-TOR-ee-uhm) noun, plural vomitoria .
A passageway to the rows of seats in a theater.
[From Latin vomitorium, from vomere (to discharge).]

Vomitoria in ancient amphitheaters helped the audience reach their seats quickly and then, at the end of the performance, leave at an equal speed (hence the name). Thousands of seats could be filled in minutes. The suggestion that a vomitorium was the place for the ancient Romans to vomit during a feast has no basis.

"Sarah Walters, 21, a university student, said: 'I love the fact that the exit sign at the station is now tagged as the vomitorium, it's very descriptive.'"
-- Paul Stokes; Metro Passengers Find Their Way to the Vomitorium; Daily Telegraph (London, UK); Mar 13, 2003.