Add ability to create Custom (User) Events

It would be really helpfull to have some kind of ability to add custom events (or something like this) to timeline.
Like now I see that temperature at our server room dropped dramatically.
I would like to click somewehere in the timeline, or rather at plase where temperature started to drop and make a small notice: Lá?a stolen door from server room.
These "Timeline Notices" should be very helpfull for teams, so users can see whats happening on the timeline.