Creating an announcement board

I would like to make something similar to this announcement board:

http://ljusasidorna.nu/kalendariet.php

Hence, something that displays coming up events, with a possibility to
limit the list by location or time.
Also with the possibility to add new events (click on "Lägg till Nytt
Inlägg" in the website above)
Surely something like this has been done in RoR? I haven't found it
yet though.
Does anybody know of anything like this, so I won't have to reinvent
the wheel?

Thanks for any help!
Fredrik