Ricky El-Qasem ovet at virtualizeplanet.com has released the Resource Pool Scheduler 1.2, it's an application that is managed with a GUI but runs a service and is used to periodically change the settings of a vSphere Resource Pool for example:
You may require to divert the CPU share allocation of a resource pool to a resource pool which is used for backup servers at 7pm and then revert the CPU share allocation back to how it was at 7am. This is useful to give the backup servers priority between the hours of 7pm and 7am.