EventedCache is an eventmachine based memcache client.  It should be ultrafast and scalable since it leverages the power 
of ragel to parse memcache protocol and the scalability of eventmachine.

EM.run{

  # connect to memcached
  cache = EventedCache.connect('localhost', 11211)

  # set a value that expires in 1 second
  cache.set('key', 'hello!', 1)

  # read the value
  cache.get('key'){ |val|
    # val.data == 'hello!'
    puts val.data
  }

  # wait for it to expire and read it again
  EM.add_timer(2){
    cache.get('key'){ |val|
      # val == nil
      puts val
    }
  }

}