Nagios ruby script - code review

Hi,

I’ve wrote my first ruby script. It’s a nagios plugin who get a full
webpage.

Main features:
* Ruby small script, easy to understand and hack (I hope) …
* http/https
* Use the powerful and simple hpricot lib to parse html
* Multi-thread
* Keyword check
* Follow redirections

I would like to have opinions and advices about this code and enhance it
if needeed.

http://code.google.com/p/nagios-check-webpage/source/browse/trunk/check_webpage.rb

Thanks,