google_calendar_oauth.rb

require "pp"
require "oauth"

key = "secret"
secret = "secret"

consumer = OAuth::Consumer.new(key, secret, {
  :site => "http://www.google.com",
  :request_token_path => "/accounts/OAuthGetRequestToken",
  :access_token_path => "/accounts/OAuthGetAccessToken",
  :authorize_path => "/accounts/OAuthAuthorizeToken"
})
access_token = OAuth::AccessToken.new(consumer)
version = "2.0"
url = "https://www.google.com/calendar/feeds/default/private/full?xoauth_requestor_id=SECRET_EMAIL"

response = access_token.request(:get, url, { 'GData-Version' => version })
pp response

output

#<Net::HTTPUnauthorized 401 Token invalid - Invalid AuthSub token. readbody=true>