Recently took up bouldering. Like BJJ it's a great way to exercise both your mind and your body. These challenging "problems" (climb talk for a climbing route) force you to come up with technical or creative ways to reach the top. After 4 trips to the climbing gym I'm confident enough to climb some hex 2's, which I think in most gyms is a v2/3. I can't recommend this sport enough, great confidence builder.