I used to have a site that was set up for pancake day, stuff to do on pancake day, about a couple of hundred different pancake recipes and so on. Every year I'd make about £200 in advertising revenue, which would pay for the hosting for other projects, some general shenanigans and (of course) my pancake day. My plan was to do something similar for other temporally-targeted holidays but valentines day was extremely competitive and easter was too big. In the end I swapped the site for a friend's laptop.