I second kettlebells :) Look up Simple and Sinister. You can squeeze a workout into 20 minutes if you crank up intensity. Ideally you do it almost every day. Th

I second kettlebells :) Look up Simple and Sinister. You can squeeze a workout into 20 minutes if you crank up intensity. Ideally you do it almost every day. The idea is that it becomes your system rather than being goal-oriented.