2009/5/20 MinuteElectron <minuteelectron(a)googlemail.com>om>:
You can find the revision number at
http://en.wikipedia.org/wiki/Special:Version and simply check out
trunk at that revision.
The problem is that that omits live hacks and individual files that
have been updated. It might leave out some critical security updates,
for instance, which are often applied to Wikimedia long before an
actual scap.
It's reasonably reliable, though, if you don't mind possibly being
vulnerable to XSS or SQL injection from time to time.