do you ever want to use the un-memoized version? if not, you might consolidate this to:

```coffee
create_redis_client = _.memoize (host, port) ->
  redis.createClient port, host, { retry_max_delay:100, connect_timeout: 500, max_attempts: 10 }
, (host, port) -> "#{host}:#{port}"
```

That way nobody will accidentally use the unmemoized version.