For people who like a fitness challenge, there is always the marathon. However, if for whatever reason that doesn’t appeal to you, the folks at the site one hundred push ups have a strength challenge for you (I think you can guess).
They have a clean, straighforward site and an easy to follow program that is challenging but achievable.
They make a good case for the program too. Check it out.
P.S. Interestingly, they just tweaked the program. I think this will make it even better. C’mon! Wouldn’t you like to be able to do 100 pushups? With this site, it’s possible.
Smart People I Know 