Mod that displays thread at a certain time

[JoeBOBBillyTed]

Does a mod exist that will make a thread display at a certain time that is determined by you? I run alot of contests and other things that need to start at specific times. This means that I stay home and post currently. I would love to instead be able to set it and forget it. If there are more then 1 of them, the ideal situation would be

Create post, set time for it to display
Some type of cron/scheduled task that is updated to display that thread, then checks for next thread to display.
Have the ability to assign this to usergroups.