I had a table of scheduled outages. Each login included a computation of the amount of time until the next scheduled down-time. The table always had TWO entries - down time and return-to-service time - and all logins except mine were disallowed during the gap between those two times. When the user logs in within 24 yours of the next down time, they got a notification in a thing that looked like (but wasn't) a Message Box (OK Only type) and a timer would start based on a little math to get to 1 hour before down time, but when THAT expired, they got a 30-minute warning, then a 15-minute warning, then 10, 5, and 1. The funky box was to prevent some bright kid from thinking they could simply ignore the OK button. The users know that when the countdown hit 0, the DB would start shutting itself down and nobody could stop it except me. At first they hated me but eventually they caught on.