See my anonymous reply to the poll The number of ways I've independently discovered to make Perl segfault:. The second one worked only in older perls. (Update: I also discovered a third way later: http://rt.perl.org/rt3/Ticket/Display.html?id=34892)

(Update: fixed typo)

Update: perl -we 'kill 11,$$' is cheating, isn't it? You can also use lots of other numbers instead of 11 of course.