We've seen several attempts at making jetpacks that fly, but over at Arizona State University, a team is developing one for those who prefer staying closer to the ground. The DARPA-funded project (naturally) is called 4MM or 4 minute mile, and it aims to develop a jetpack that can provide soldiers that extra boost needed to run a full mile within four minutes. Sure, soldiers are physically fit, but the jetpack will make sure each one can do a 4-minute mile, even if they're not particularly fast runners, and even if they're carrying heavy equipment and armor.