Between federal employment and various volunteer endeavors, it seems I am always looking for ways to connect easily that doesn't cost anything. My first month in my civilian job we were organizing a meeting for about 100 people, and collecting RSVPs and lunch orders by e-mail. Arg. And nearly impossible to do well. Where was the civilian version of AFIT's E-Invitations? Obviously there are sites like Evite, Team Snap and Signup Genius (great tools for other functions) but I needed something less...social.
A quick google search and I found Whoozin. It has been a great way to host our monthly and quarterly meetings, especially because you can copy events if you are having multiple meetings with the same group. As we've added invitees over time it's been a great way to collect an awesome contact list. There are paying parts of Whoozin but all the functions I have used have been free. I haven't come across any indications of adds or spam as a result of using it.
My second recommendation is FreeConferenceCall.com. I actually set up a number when I was still in the Air Force. I had about 8 active duty and civilians spread across 4 regional FAA officers, not co-located with a base. We had a mission to get done, and we needed to stay in close contact to support each other. It sounds a little whiney, but having to pre-schedule a conference call through the DoD that would automatically cut off at the scheduled time, regardless of your need to continue your conversation, got a little old. FreeConferenceCall worked out really well, and I have used the number for quick family convos and for one of my volunteer projects. It has never been a problem, and I have never had an issue with spam.