1. Answer the question, "Why?"
When I started out as a speaker, I was told to use a grabber--a snappy, attention-getting opening sentence designed to pull people out of their own heads and get them interested in what's in yours.
But I noticed that anytime I was listening to a really good speaker, they weren't so concerned with the showy stuff at the start. They were more concerned about posing this question: Why is it urgently important that we discuss this topic?
Maybe a story, or a joke, or a news item from the paper can work. But using tricks and shtick to get attention may not draw them into the topic, and it could hurt your credibility. You don't want to do the equivalent of the disappearing bunny trick to get them to focus on your serious talk.
Providing answers to the "Why" question is the better, more credible, and meaningful way to open your talk