The Gunnar Challenge offers new workouts every day, a meal plan and daily 'verbal vitamins,' which are a motivational video or workout tip. The thing that really makes the program work is the forum, where Challengers can communicate with each other and with me.
If you were inactive due to an injury or a surgery, then common sense rules the day when inching closer to the area that was hurt. That is very different from inactivity due to being ill. After illness, be aware of how taxing your workout is cardiovascularly and err on the side of less.
Multi-joint movements - squats, push-ups, bent over rows - all put a greater metabolic demand on the body and can be effective when performed with very light weight to get you back up and running. Think bigger movements, not bigger weight, when you are on the mend