There are many good exercises you can do for a muscle workout without the typical machines.  The best exercises are those that concentrate on specific muscle groups and that can be done with free weights.  If you don’t even have access to free weights, you can use a heavy textbook or make a sandbag.  If you prefer more exercises that use your own weight as resistance, try pull-ups, push-ups, sit-ups, squats and lunges.  If staying inside bores you, you can always take your moves outside.  Use a sturdy tree branch as a pull-up bar and try and push the tree as hard you can to work both your arms and legs.

Any intense exercise move that works key muscle groups is going to build muscle, and you should target one muscle group each day you workout to maximize your efforts.  For example, on Monday do sandbag curls, dips and dumbbell style kick backs to work out your biceps and triceps.  On Wednesday, try bench pressing the sandbag, and chest fly’s to work out your chest and back.  On Friday, do squats, and lunges to work your legs and over head press and lateral raise, again with the sandbag, to work out your shoulders.  Tuesday, Thursday, Saturday and Sunday should all be your rest days.