What to do for atheist funeral?

My mother passed away recently. Luckily, we got a chance to discuss final wishes with her before it happened, and the only thing she was sure about was there was to be no religious content at all. Both my mother and father have been strict atheists for as long as I can remember, they raised me to look at all the information available and decide for myself, and I became an atheist as well.

My family wants to hold a ceremony, but we've only ever been to traditional religious funerals before, and we aren't really sure of how to go about it. Do any of you have experience with this matter? Is there a protocol for this sort of thing?