Factorial

Score: 53.13 (pass)

Finally remembered that I know how to get rid of $ARGV[0]!

#!perl -l
for(++$p..pop){$_*=$p;/0*$/;$p=$`%10**6}print$p%10

Score: 58.15 (pass)

Just something to get going I suppose.

#!perl -l
for(++$p..$ARGV[0]){$_*=$p;/0*$/;$p=$`%10**6}print$p%10