I would want to do (may be you want to do yourself and push request to github?:)
But if upi want to help please let me know before (may be i do it right now)

    - Non blocking execution. I want to have options for 'run' method if cache
      value is needed recomputed we should not recomputed it but we should
      return either old value or 'undef'. For example if we have a site and it
      visited by Google bot we will prefer generate for it quickly page from old
      data and recalculate it later by background process for example or may be
      to be not recalculated. Google bot will not wait of recomputing or access
      time of page will not good for us in Google statistics.

    - For non blocking 'run' executions we will want to have ability to
      recompute these tasks later in a background process. I think better to
      have a queue of targets for recomputing and method like $cascade->queue()
      for background processes. For example code of this process would be as:

	while (1) { $cascade->queue; sleep 1 }

	OR

	while (1) { $cascade->run('queue_target'); sleep 1 }

      The queue can be kept in cache too and may be it will be simple target

    - To need corrections of my English in docs (my English is not well as i
      want)
