I don’t know how “fun” a mail server can be. They can be amusing…and sexy…*day-dream* But I like how the Hula Project is thinking about scalability from the ground up. Of course, I’d do anything to never have to look at that horrible yellow M$ Exchange Server screen again 
Hula is a calendar and mail server whose goal is to be fun and easy to use, while scaling effortlessly from small groups to large organizations with thousands of members.
