Based on exactly what you want, DotNetNuke has everything you need for free.

The FREE Forum module (which is the same as this one) is very good even though they are having an issue with notifications.  Activeforums is an execellent module and if you only need 1 group/ 3 forums then you can use it for free.  For unlimited groups/forums you will need to pay 49.95.

Calendar/Event:  The FREE Event module (specially 4.01.00 RC3) is a fantastic Event module IMHO.  The only con would be it needs a more robust event registration function.  Members can sign up for events but they cannot add additional people under their registration.

I believe you will be able to find free alternatives for most of what you want.

Michael

Well, you know you ran into a brainiac here... I hit "next" in the bottom just before hitting reply.  And then to hurl a positive confirmation that I am an idiot... I posted another to the wrong thread.

VERY good response(s) here, took the time to look the suggestions.  The're all keepers.  Excellent forums, in my favorites!

AND

Worried about putting my cudos in there so much, forgot to ask, is this forum an available DNN module?

were both posts for this thread, yes I checked twice this time.  Still wondering, is this forum an available module for DNN?