"There is nothing better for a person than that he should eat and drink and find enjoyment in his toil. This also, I saw, is from the hand of God, for apart from him who can eat or who can have enjoyment?"
Utilizing a versa-climber, airdyne, rower, or a good old fashion vertical hill perform 10 sec of max effort sprinting followed by 20 sec of rest for a total of five minutes. Rest and repeat.
High intensity intervals are by far one of my favorite tools to condition the body. We're talking 5-10 minutes of work here and your done! As with all things you get out of it what you put into it. To simply go through the motions and avoid truly expelling hard effort and work will accomplish nothing and waste your time. Invest yourself into the effort and you will be investing yourself into, well yourself. You are the determining factor! This goes for most things in life. All choices have been given to us, we just can't always see them for what they are, but they are there...