In fact, researchers have found that burpees are just as good, if not better, at maintaining fitness levels as more traditional high-intensity interval work -- even when people do them for a shorter period of time. So, yeah, burpees are king.
There are a number of burpee progressions, ranging from low-impact to high-impact, so start with the most basic version and work your way up from there:
Stand tall, your feet shoulder-width apart, your knees slightly bent, your core engaged. Crouch down, placing your palms on the ground under your shoulders. One at a time, step each leg back so you're in a high-plank or push-up position, your body forming a straight line from heels to head. Immediately step each leg forward again to your crouched position, then stand tall. Repeat these steps as fast as you can with good form for 30 seconds. Rest for two to four minutes, and repeat. Perform four to eight sets.