Who gets bored doing weights in a gym or at home?  I have been bored with them for a while so I am trying to mix it up.  Now that Minnesota has been blessed with some warm weather I have been trying to take my clients up to the playground for a workout-just body weight and the monkey bars!  I love the low parallel bars that you can do dips on as well as inverted rows.  By inverted rows I mean have your body at an angle with your heels in the ground and pull your body up so your chest hits the bar.  Slowly lower, keeping your shoulders back and down, then repeat.  You goal is not to let your hips/butt sag and keep your back straight.  This will work your shoulders, biceps, back, etc.  If you find it is too hard to pull up at that angle, flatten your feet, keeping as little weight as possible on them.  This will give you more help, but still challenge you!  Start with an underhand grip, keeping your hands shoulder width apart, however, you can advance to using an overhand grip and widening your hands so your arms are bent at a 90 degree angle. 
I mentioned dips before, if you can't lower and raise yourself using your body weight and the parallel bars, you can uses a bench and either put your legs straight out in front of you, staying on your heels and keeping your back close to the bench, or you can bend your knees at a 90 degree angle and keep your feet flat.  Make sure your elbows are pointed straight back and you are keeping your arms close to the sides of your body. 
And of course one of my favorites is to do a plank-in a push up position, but keep your arms bent at a 90 degree angle with forearms on the ground and up on your toes.  Make sure your hips/butt aren't sagging and you have a flat back.  Hold for 30 seconds and work up to to 1 minute.  If you want an additional challenge, pick up one foot and hold it up, then after 30 seconds, switch to the other foot and hold for another 30 seconds. 
You can always bring a band with to do rows, or bicep curls, but challenge yourself with the equipment or your body weight in other ways-swing across the monkey bars, do lunges with your back foot up on a step or bench, or do walking lunges around the perimeter of the playground (watch that knee so you don't go past a 90 degree angle!).  Do a set then run or walk around the playground and do another set!  Remember you don't have to spend an hour doing this, just get your body moving and have fun!
I will add pictures tomorrow of these exercises because i know sometimes that is easier than trying to visualize, especially if the explanations aren't making any sense to you!