Is it possible to use Ruby to design a discrete event simulator using
coroutines?  I'm looking for something like the generators in Python 2.2, is
there something like this in Ruby?  The callcc method seems far too
expensive (looks like each one is about 14-15k in Windows XP), and the yield
method seems to return only to a passed in code block, not back to the
caller (I think, I'm new to Ruby).

Thanks,
Ken