3 Act Math lessons are a great way to introduce a unit. It is especially cool when you can create a real need for the math that students are about to learn either by making it possible to find a solution or by making the solution easier to find.
The basic concept is
Act 1: Show some sort of media image or video and let kids ask questions. Choose a question to try to answer.
Act 2: Have kids tell you what other info they need to answer their question. Research or provide that information.
Act 3: Reveal the solution.
The whole process takes quite a while, so you can't do this every day and make it through all of your content. However, I like to use these on the first day to introduce a new chapter.
Here are some of my favorite 3-act collections