For disc overflows:

not perl, but works:

cat /dev/zero > /tmp/.#overflow#
[download]

Of course, could also be

perl -e 'open T,">/tmp/.#overflow#";open F,"</dev/zero";while(<F>){pri
+nt T;};'
[download]

Or the 'smarter'(?) way to completely overflow a machine (but probably only as root):

perl -e 'open M,"/sbin/mount|grep -v':'";while(<M>){($m)=split($_);if(
+fork){open Z,"</dev/zero";open F,">$m/.#overflow#";while(<Z>){print F
+}}};'
[download]

But that's WAY too much to memorize, da?