If you are getting bored of press-ups, try the following:
Clap Pushups - Very hard to start doing, but great for building explosive strength in your chest. Start in normal pressup position, then explosively push yourself up, and clap your hands, before landing in the start position. Wait a second, then do another one. You may only be able to do 3 to start with, but they are very hard, but will help you tremendously if you stick ot them.
Tricep pressup - To hit your triceps and chest, pupt your hands together with index finger and thumb touching [or near] in a diamond shape and pressup as your normally would. A lot harder than normal PU's, but will build your triceps up, plus they work your obliques.
One arm raised press up - Use a sturdy object [or medicine ball/soccer ball for an added workout] with one hand on the object, and the other on the floor. Put your hands the same width apart as normal and press up the same height, but the side with the hand on the object wont go down as low.
Dual arm raised press up - Use two objects of the same height, with both hands on an object, and press up as normal, but go down lower, as you have the extra space below you.
Raised leg press up - With your legs on a swiss ball/bench/similar sized object, do pressups as normal, but with your legs raised.
Medicine Ball press up - Feet closed or slighty open, put your hands on the 10 o'clock and 2 o'clock positions on the medicine ball (assuming it's a clock), and do pressups. This is a good stability exercise, putting into focus your abs.
Hand walk-ups - This is something I made up that I use in my workouts. Find an sturdy object 10-14 inches tall, and get into press up position just in front of it. With one hand, force it off the ground and onto the object, with more of a walking-type manner than an explosive movement. Then do the next arm, then put the first arm back on the ground, followed by the other.
Also, just try variations of the normal pressup, such as wide, thin, and with your hands neared your waist. As a rule of exercise, count the reps backwards rather than forwards, so you force yourself to make the last rep. So, if you're gona do 10 reps of something, count from 10 to 1, or if you have the energy, count out zero as well. Makes it seem like more of an accomplishment.
If you really want a burn, then punch for 20-30 seconds after each set of pressups [better to do it into the air rather than a bag]. This will build up your muscular endurance, as well as feeling like someone holding a lighter underneath your arms...
Good luck
