My latest attempt to exercise every day. I figure even I can spare 7 minutes on the busy ones.
http://well.blogs.nytimes.com/2013/05/09/the-scientific-7-minute-workout/
Use this (I tried them all, this is the best):
https://itunes.apple.com/us/app/gymboss-2-interval-timer/
Configure like this (note the sounds come after the interval when choosing):
mikehardy.com 