Rails::Initializer.run do |config|
  # ...
  config.action_controller.session_store = :mem_cache_store
  # ...
end 

CACHE = MemCache.new :namespace => 'memcache_recipe', :readonly => false
CACHE.servers = 'www.tupleshop.com:11211'

ActionController::Base.session_options[:cache] = CACHE