Rowing/Biking and Double Unders
Today, if you had a decent double under, you could have a decent time. I love the fact that doing double unders is different when you are in the middle of a WOD versus just beginning. You have to concentrate to make it work. It's another reason why CrossFit is so effective. It teaches you to work at a good pace while being coordinated in various movement patterns. This has to be great for the brain.