shelleycat
One of the easiest (well, if you're not afraid of needles that is) thing that men especially can do for their health is to give blood regularly, like once a year. Women who are menopausal and no longer menstruating should give blood too.
Since men don't lose blood like we women do, they get into what's known as "tired blood syndrome." One of the liver's main job - out of its 500 jobs - is to take dead and dying red blood cells out of circulation. This is what gets turned into Bilirubin, the main coloring agent in fecal matter.
When the liver gets behind on this job, the body still thinks it has a full complement of red blood cells and doesn't produce more. The dead and dying cells are still counted as active cells by the body's gauge. By giving blood, this gets rid of the dead and dying cells and lowers the number of total blood cells, thus triggering the body to make more. This increases your body's ability to oxygenate, and of course oxygen is required by every energy exchange there is.
So give blood! :)