I keep finding my self having to deal with users who's passwords are expiring (as in tomorrow) but have no access to a computer to reset it. For unknown reasons, said user cannot have their password change and thus its expiration MUST be extended. If only they'd read those "your password is expiring in 10/2 days" e-mails (all a sysadmin can do is try). Yet another script that perhaps I'll write about one day.
Anyway, below is a script I put together to quickly bump a user's pwdLastSet to the current day. PwdLastSet is what AD uses in addition to the domain's max password age to calculate when a user's password expires. The description in the script below gives an example of this. Similar to my other scripts, look past the boiler plate function and the code is pretty simple. Throw in the -verbose parameter so you can see what's happening. A word of caution, this script takes pipeline input and has the ability to mass expire passwords. That said, test it first in a test/dev environment.