We've got a Software restriction GPO setup and I was wondering if it was possible to make this only active during certain times.
For example, only make certain game executables available to use at lunch times.
Running Server 2012.
Not with any of the vanilla Windows tools, I'm afraid. This is where classroom management solutions (Tutor, Impero etc) come in,
yes it is possible with WMI filters however users would have to run manually gpupdate or wait for the policy to refresh. Remember that default refresh every 90 minutes by default, with a random offset of 0 to 30 minutes - take that into account. You can adjust this too.
so if day of the week is possible then a specific time would also be possible and indeed it is : source: http://msdn.microsoft.com/en-us/library/aa394171%28v=vs.85%29.aspx
class Win32_LocalTime : Win32_CurrentTime
Secondary options / enchancement:
Schedule via GPO 2 tasks:
however a user could always copy the program to another location and run it.