Day 6 minimalist calisthenics workout using nothing but a pull up bar. Wide grip pull ups, push ups, and walking lunges. My work schedule forced me to knock this out with minimal rest, which inspired me to discuss the subject of rest intervals.
How long should you rest? The real answer... as long as it takes for your to perform as well as you can on your next set! However, if you are short on time, but want to get the reps in, you can make up for a poor quality set due to lack of rest with a more sets, but you would probably be better off making sure you are adequately rested between sets.