What are some good warmup exercises to do before starting any of the Challenge (Pushups/Situps/Pullups/Squats) apps or 7 minute workout?

Some good warmups in general are jumping jacks or running in place. This is just to get the heart rate going. Some of our users like to stretch the muscles that they are about to exercise (chest, glutes, abs) etc. The following 2 videos are our personal favorites for full body stretches, as they give great instruction and the routine can be done in 5 minutes!