Block Party

I am planning a party for all the neighbors in our building to (hopefully) attend. This is a group of people who come from all walks of life. The only thing that some may have in common with another is the fact that we live in this building together.
But I think it is long past due that we become more neighborly with our neighbors. So we are being the brave ones to host a "gathering. " I am going to make the invites up tonight, but I am really wondering what all I should have to do... We have cards, board games, and the wii, and food and drinks. What else do you think I should have/offer? Or do you think they would actually come and have fun for 2 hours just talking and listening to music?
That's another thing... what kind of music should we have? What's good all around?