There are a couple of possible approaches, depending on your server setup. If your Windows domain has an authoritative time server running, your servers should be able to synchronize using the W32Time service. Once they are, InterMapper’s WMI Service probe can be used to monitor W32Time on the servers and alarm if the service exits.

Another approach (and one which applies to Linux or OS X as well as Windows) is to enable SNMP on the servers and use the Servers-Standard > Host Resources probe to monitor them. The Status Window for the device will then show its reported day and time as of the last poll response. The HR probe converts the hrSystemDate object’s value to a date and time as shown in the Status Window output for the HR probe in the attached screenshot, which also shows the Status Window output for a  SNMP > Basic OID probe looking at the same object (and displaying it unconverted from the returned format).

A custom SNMP probe doing the same conversion the Host Resources probe does should be able to provide output which could be used in the label for the device on the map, so that it could be displayed without the necessity of opening the device Status Window.