Does anyone know how to do the following, but without threads, purely 
with asynchronous IO?

website = Thread.new{ Net::HTTP.get(URI.parse(url)) }
template = compute_lots_of_stuff()
puts template.sub("<content goes here>", website.value)

I'm not sure I understand EventMachine, but it doesn't seem like this 
code fits with the "event loop" model. Besides, I don't want to react to 
every chunk of data that comes it; I just want the result at the end.

Thanks.