While reading the regex portion of Apress’s Beginning Perl Second Edition by James Lee, the following sample code totally made my day.
#!/usr/bin/perl -w
use strict;
$_ = "There are two major products that came out of Berkeley: LSD and UNIX";
s/(\w+)\s+(\w+)/$2 $1/;
$_ = ucfirst($_);
print $_, "?\n";