What I like to use for 'active recovery' is more functional fitness workouts, which may use weights, but they are lighter. Also some moderate cardio, flexibility/yoga (or joint mobility, my latest discovery).
These kinds of workouts are beneficial, IMO, because they train the supporting muscles (the deeper muscles vs. the superficial muscles that most weight training focuses on) and can help prevent injury and increase effectiveness of heavy weight workouts when you get back into them.
And though you may fear losing your muscle, you may be surprised to find you make some gains during that week, as the hard-worked muscles have time to repair. And after a relative rest, they will be all the more ready to take on the rest of the challenge.
