Greg McIntyre wrote:
> Thanks to all of you who answered and cleared up some of my perceptions
> about Python. As a result I've put together some slides introducing Ruby
> to Python programmers (hopefully without any misinformation!).
> 
> This is a 30 minute lecture on Ruby, aimed at 3rd year university
> students who have just learnt Python. Feedback welcome.
> 
> http://www.cse.unsw.edu.au/~gregm/secret/ssdi/lectures/

Despite my comments and corrections, it is a pretty good set of slides. 
If you want more for the Ruby side, you could add syntax-integrated 
regular expressions and continuations (though those are a little esoteric).

  * http://www.rubygarden.org/ruby?Continuations

I found this page on how you can emulate generators with continuations:

  * http://www.rubygarden.org/ruby?RubyFromPython

Also, Ruby has "microthreads" which are better in many circumstances 
than OS threads (which are better in other circumstances). To get 
microthreads in Python you need to use the Stackless fork. To be honest, 
I think that OS threads tend to be more useful more often but opinions 
could vary.

  Paul Prescod