Pesäpallo is a Finnish variant of baseball, and it’s incredibly unique – the bases are on an asymmetrical zigzag and the ball is pitched straight in the air. In terms of play, it’s only vaguely like baseball and very strategic – hitting the ball out of the park is foul, not a home run, so you need to be able to target exactly where you want to ball to go – and also decide if you want to run at all. I watched the below video on the rules, then re-read through the Wikipedia article, and while I wouldn’t count myself as being able to completely follow, I think I have a rough idea how it works.
There’s a few full games posted online, though they’re all in Finnish – however, once you stop thinking of it as “different baseball” and think of it as its own sport, it gets a bit easier to follow. Here’s a little compilation for flavour:
That all being said, how popular is pesäpallo in Finland? It’s alleged to be the national sport, since it’s a truly Finnish creation – it was created in the 20s in the wake of Finnish independence with an eye to keep young men fit and active and thinking strategically for military duty. There’s a really interesting article on the creation and history of the spot at Virtually Nordic – it also touches on the small but dedicated following pesäpallo has in India, of all places.
However, currently pesäpallo seems to have the same kind of status in Finland that lacrosse has here in Canada – it’s the “national sport”, but as explained below, nobody swims in a fountain when you win the championships.