I'm posting this in hopes that search engines grab it and put it at the top of their list when other poor soul's run into this problem.
If you're trying to grab a web resource using Open-URI, and you are using basic authentication (username/password) then you'll need to make sure to
require 'open-uri' or you'll get:
open("http://example.com/site", :http_basic_authentication => ["username", "password"])
TypeError: can't convert Hash into String
Of course, then you toss some yummy Hpricot into the mix for parsing/scraping the good bits of the HTML.