How do you effectively talk to someone in loud environments?

I've been to a few "high-energy" events over the years, such as weddings and company holiday parties. In my experience, people at those events tend to be more open to conversation. But at the same time, it's often hard to talk over the music because the volume is turned way up. I practically have to yell for people to hear me.

Does anyone have any tips for those situations?

It doesn't really help that most people don't know sign language or telepathy. :P