Eli Bendersky's website I've been planning to do this for a long time - write a MIX/MIXAL (the machine language from Knuth's book) interpreter & simulator in Perl. There is a robust C implementation - the GNU MDK, but no real Perl implementation (as far as I know, from searching CPAN and the web).
Well, I finally started - by reading some material. The GNU MDK's user manual explains the instruction very clearly (better than Knuth himself), so I'm going over it now. Maybe it seems simpler because I've read Knuth's coverage of MIX/MIXAL already =)
Anywayz, if anyone knows of some MIX related Perl stuff, let me know ASAP please.