If you turn to the app ecosystem on your smartphone, you are bound to find an app for every possible mundane chore, and then some. There is a pedometer for your daily run, note-taking app for your recipes, list-making app for grocery trips and even an app that tracks your sleep cycles. But what about the important tasks at work? Could an app help you sort out the leave calendar for your team? David Duffield and Aneel Bhusri decided to take a stab at it and founded Workday in 2005. By 2006, they had the eponymous human resources app ready. Busy professionals can subscribe for the service, which is available on most mobile devices and software platforms, and have a gathering of personnel management services at their disposal instantly. With close to 300 firms signing up with Workday, the app definitely seems to have found takers, netting $119.5 million in revenue last year.