Brainstorming is a creativity technique in which a group of people (or an individual person) spontaneously generates a set of ideas to find the solution to a particular problem. This paper describes an innovative approach called "brainstorming with yo-yos," which was implemented in an outreach to high school event to increase high school students' interest in learning physics and consequently pursuing postsecondary STEM education. In this approach, student teams identify, via collaborative brainstorming, as many yo-yo-related physics concepts as possible, and thus students can connect what they learn in the K-12 classroom to real-world applications. A total of 122 high school students, including 91 males and 31 females, from different school districts across the author's state participated in "brainstorming with yo-yos" activities in a recent summer. Student teams identified more than 50 physics concepts. Student comments were also highly positive. Many students used words and phrases such as "fun," "play," "hands on," and "real life," to describe their experiences with the brainstorming activities. Based on a close examination of students' submissions of physics concepts, it is suggested that instructors incorporate the mind mapping technique into brainstorming activities to make brainstorming more effective and to simultaneously enhance student learning.