This may well have been suggested before, but: what if there
were a variant on Special:Random that somehow gave you a random
article in a category of your choice?
This popped into my head while thinking of better ways to
announce cleanup crusades (better, say, than proposing that
everyone take an hour out of navel gazing on the mailing lists
and instead select N articles from Special:Random and clean
them up), but it'd probably have plenty of other practical
applications, too.