test.rb

require 'selenium-webdriver'

wait   = Selenium::WebDriver::Wait.new
driver = Selenium::WebDriver.for :firefox

driver.get "http://www.google.no/?as_qdr=all"
driver.find_element(:name => "q").send_keys("selenium")

suggestions = nil

wait.until { 
  suggestions = driver.find_elements(:class => "gsq_a").select { |e| e.displayed? }
  suggestions.any?
}

suggestions.last.click