4
I'd recommend you look at the
CatAds module or maybe even just one of the blog modules that would allow a freeform "announcement". The CatAds module is good for selling items but wouldn't necessarily be good for announcing an upcoming event. You could allow this with one of the multi-user blogs.
Another option would be to combine modules and give your users rights to create items. For example using CatAds with a calendar module (say PiCal or eXtCal). You could then show the newest events on your top page - so they look like announcments.
