Automatic disappearing Posts

I want to have some important Post's show up in a sidebar. However, when whatever that important Post is talking about expires, I want the Post to disappear. I know it's similar to an Event but I don't want to include it with the event's. For example, let's say that I want to have information about our American Legion Baseball team playing in the play-offs, and I want my users to know how they are doing and when their next game is. Then after that game, or special event, I want the Post is disappear.

I want as little manual intervention as possible.

Is this possible and how would I implement it?

Thanks, oh, and I'm working in a sandbox until its time to go live with my site.

Dave