Hi,

I run ecl (http://ecls.sourceforge.net/), embedded common lisp, on
my powerbook.  It really is fairly fast and for what I use it for the 540
works well.  It makes a nice portable lisp station.  I also like my 540
to carry around because it's not too heavy, and, I have like 6 of them so
if one gets lost/dropped/stolen/etc I don't really care.

Note that ecl has a few issues on the 68k systems because it uses the
Gnu Multi-Precission library and that has some problems on 68k systems.
It's not bothered me enough to fix it but if you build ecl you'll need
to have a build from another system (ppc or x86 work well) to copy files
from when ecl crashes in it's build process.

cheers

bruce