NightmareOzzie is working on 43 things
Wow, sounds fun!
How I did it: Tour bus from Beijing. It's a great experience to walk on the wall. But, there are some kind of sad drawbacks -- aggressive vendors are lining the entire length of the Great Wall trying to sell stupid trinkets. New China means selling out and putting giant billboards along the stretch of the Great Wall too.
Best part was buying stupid Mongol hats and re-enacting the Mongol hordes invading over the wall.