As a man of little substance and even less will-power, the only way I will actually complete this is to make it look like I'm letting down a children's charity if I don't do it - the power of shame and embarrassment.

47,000 press ups is 128 per day every day for a year, so if you see me and have some spare change in your pocket, by all means throw it at me in exchange for 'dropping and giving 10/20/40'.  You could even join me as extra motivation.