When it comes to health benefits, there are many counterintuitive examples and laughter is right near the top. Few guys would ever guess just how important humor and laughter could be to their future. As it turns out, those you who are serious about your health - well, you may just want to not be so serious. A little levity, it turns out, may go a long ways.
Laughter is, quite simply, as powerful and potent as any drug and all without side effects. Here are four key benefits laughter can provide for you:
1) Growth Hormone. One of the most powerful "fat-burning" hormones is HGH (Human Growth Hormone). There is also evidence that HGH aids muscle growth somewhat as well. Laughter, according to one older study, strongly increases (by 80%) HGH levels.  That means that "laughing your ass off" may be quite literally true.
2) HDL. Good cholesterol, unless your are on a Low Fat (Ornish) Diet, is critically important to your heart health. HDL is also a potent stimulator of Nitric Oxide. Another just-downright-amazing benefit of laughter is that it increased HDL levels in diabetic patients by an impressive 26%. 
3) C-Reactive (Inflammation) Levels. C-Reactive protein, a measure of system inflammation, is a well-known risk factor for arterial disease. The reason? Inflammation is one step in the process that damages arterial linings and, in the aftermath, leaves the infamous plaques that causes arteriosclerosis. Research has shown that elevated C-Reactive protein levels also leads to penile arterial disease, i.e. erectile dysfunction and impotence.  Laughter, it turns out, is a powerful anti-inflammatory tonic and significantly lowers C-Reactive protein levels by an astonishing 66%. 
4) Cortisol. The same study that found laughter's boost in growth hormone also found that laughter significantly reduces cortisol as well.  Elevated cortisol levels damage the brain, increase visceral fat and lower testosterone.
So, as odd as it may seem, laughter is likely a huge protector of all you hold dearest as a male: your sex life, your hormones and your brain. What other benefits do you need, eh?
1) Am J Med Sci, 1989 Dec, 298(6):390-6, "Neuroendocrine and stress hormone changes during mirthful laughter"
2) Presented at the 122nd Annual Meeting of the American Physiological Society, Apri 18-22 New Orleans Experimental Biology 2009 scientific conference, "Mirthful Laughter, As Adjunct Therapy in Diabetic Care, Increases HDL Cholesterol and Attenuates Inflammatory Cytokines and hs-CRP and Possible CVD Risk", Birk, Tan.
3) International Journal of Impotence Research, 2003, 15:231 236, "Relation of C-reactive protein and other cardiovascular risk factors to penile vascular disease in men with erectile dysfunction"
4) Presented at the 122nd Annual Meeting of the American Physiological Society, Apri 18-22 New Orleans Experimental Biology 2009 scientific conference, "Mirthful Laughter, As Adjunct Therapy in Diabetic Care, Increases HDL Cholesterol and Attenuates Inflammatory Cytokines and hs-CRP and Possible CVD Risk", Birk, Tan.