Nifty perl programs for biology

[Steven E. Brenner]

As a follow-up to my previous message, can people let me know of any
"cool programs" they've done in Perl, or using biological data?

One example I plan to show, to introduce biological data, is a FASTA query
of "random" sequence which turns out to code for some important
disease gene.  I think that will impress on much of the audience the
power and importance of computers for biology. 

However, I'd also like to show some more Perl-y typical or
particularly interesting programs/manipulations/operations.  

Thanks in advance,

  Steve