What CMS should I use for a COMMUNITY WEBSITE?

I need to put up a website for a small community.
I was thinking of using something simple.
But I desperately need an easy-manageable event calendar that I can
display on the fronpage.
I also need a forum or something where users must sign-up using a their
contact-data.
I would love it if users' photos would show up near the messages they
post on the forum.
I would love it even more if it this CMS had a plugin to show a
photostream on the website.
A nice feature would be a script for showing when's the next birthday
to the group members.

Can you please give me an advice? What CMS should I use?

Thank you!

Super simple one at www.webmodules.com it's free and easy to use- even
has an event manager and calendar already built.