According to Jules Verne you can go around the world. Today with air travel it takes a lot less time, though with the limited leg room in economy class it feels like 80 days.
How about writing a novel?
If you missed NaNoWriMo here’s your chance. May – You Write Your Novel Challenge.
The challenge is to write 80,000 words in 80 days beginning on 1st May and ending on 19th July. The idea is to write the first draft of an 80k novel. First draft note, not a masterpiece, you're allowed to edit later!
If you wanted some motivation to get started on your idea, a kick up the pants, or just to know there are other writers out there slaving over a hot keyboard have a look at the blog.