snippet.rb

require 'open-uri'

content = nil
puts "Valid cert:"
open("https://www.wesabe.com") { |s| content = s.read }
puts "  got #{content.length} bytes"

puts "Invalid cert: "
open("https://google.com") { |s| content = s.read }
puts "  got #{content.length} bytes"

# Output:
#
# Valid cert:
#   got 12199 bytes
# Invalid cert: 
# /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/openssl/ssl.rb:123:in `post_connection_check': hostname was not match with the server certificate (OpenSSL::SSL::SSLError)
#   ...