One interesting use that is (as far as I know) unique to Perl, is using the trinary as an Lvalue. That is on the left hand-side of an assignment as in this (rather silly) example.

#! perl -sw
use strict;

my (@aboveC, @cOrLess);

while (<DATA>) {
    # $1 := name, $2 := grade
    m/^(\w+)\s+([a-f][+-]?)$/i;

    # if the grade is one of these
    0<= index('A+ A A- B+ B B- C+', uc($2), 0 )
        # add name here    if not add name here
        ? $aboveC[@aboveC] : $cOrLess[@cOrLess] = $1;
}

print "Above C   students: @aboveC\n";
print "C or Less students: @cOrLess\n";

__DATA__
homer    f
bart    d-
marge    c+
lisa    a
[download]

which gives

C:\test>195952
Above C   students: marge lisa
C or Less students: homer bart

C:\test>
[download]