Board Press - Nail or 2, 3 or 5 two by sixes together that are 12 - 18 inches long. While laying on your back on a bench, have a spotter hold the boards on your chest. Take the bar out of the rack just as for a regular bench, except that instead of lowering the bar to your chest, you lower the bar to the boards, which will obviously shorten your bench stroke. Pause the bar on the boards for just a second, then forcefully press back to lockout. I use this exercise for a max effort exercise, meaning that I max out up to a single on this exercise.
J.M. Press - this is a tricep builder. Grip the bench bar very narrow, for me about an inch or so off the smooth part of the bar. Take the bar out of the rack as if benching, then lower the bar toward the upper chest, stopping the bar at the worst possible leverage point (4-6 inches above the chest) and press back to lockout. Keep elbows jammed into your sides, don't let them get away from your body. (this is also true when benching)
Hope this helps. You should be able to go pretty heavy relative to your bench on both of these exercises. I have done a 3 board press with 385 lbs of bar weight with over 100 lbs of band tension, and have done a JM Press with 315 for 4, relative to a bench in the 480 to 500 range.