Active Directory management.

repadmin /showreps servername – Domain Controller replication status.
repadmin /replsum – replication status of all the domain controllers in the forest.

dsquery user -stalepwd <NumDaysSinceLastPwdChange> – Users Whose Passwords Are About to Expire
dsquery user -inactive <NumWeeks> – Users Who Have Not Logged On Recently
dsquery computer domainroot -inactive <NumWeeks> – inactive computers in the current domain

dcdiag /s:server-name – Test DC status (replication etc)

rsop.msc – (Resultant Set of Policy) Shows Group Policy settings that have been applied on a local computer