There should be the ability to select a single node or collection of nodes and mark them not to trigger alerts indefinitely or for a period of time and then later turn them back on. This is all without stopping monitoring, just the alerts.
Right now someone suggested adding a custom property to every node and then in every alert we create test to make sure the node has a certain value for that property. Seems like a hack job for something that should be built in (no offense to the person suggesting this).