Gambit is now available online, running inside of emacs:

http://feeley.github.io/gambit-in-emacs-in-the-browser/

Try (load "bench"), then (begin (step) (fib 3)) followed by a few M-s (single step) and then M-c (continue), then (fib 'err).

If you prefer Gambit running in a terminal then use this instead:

http://feeley.github.io/gambit-in-the-browser/

Marc

P.S. Happy thanksgiving… one day late!