if you do cardio and you like zombie movies then the Zombies Run App. .. ive been using that for a few years when im getting ready to run a race shit is fun and scary...i know alot of guys on here are to cool for cardio though.
i will say this i found a cool app only cause i'm lazy and am horrible with math in my head. app called Weighter Plater. you set the weight of the barbell. once you got that you enter the weight you are lifting and it tells you what size plates to use. simple little cheat app. takes out all of the guess work. btw its only for android. might be able to find a different app that works the same for iphone.