With this plugin you can allow topic owners in selected forums add their own open hours for their 'topics' - those could be their businesses, private lessons and any other kind of services which they are providing.
It will show if they are 'opened' now or not etc. It's great addon for a beautician, mechanic, plumber, computer service etc.
If you want to add new place where the status open/closed should be displayed - let me know. I'll see what I can do with this and try add it.