I know laughing at another person's expense is really bad karma but I see some scary things at open gyms and rec centers. Here is a simple but effective workout you can do at home with or without weights.
12 ---- side lunge (right) - squat - side lunge (left) Note: count only your squats
10 ----- hand release push ups
10 ------- bent over row or pull up if you have a bar
10 ---- Vsits + 20 Russian twists
20 ----- mountain climbers Note: count one rep when only your right leg comes forward.