I think something that is very nice about Finland is that many areas provide fireplaces for making a bonfire. There are some in Ruissalo as far as I know and also some near the lake in Turku. I went all up to Seinäjoki to make a campfire and it was really nice. It was on my to do list in Finland because I think with the cold weather it is very nice to just sit around on benches in the woods with snow all around you and a fire in the middle. In Seinäjoki it was also very cool because near the fireside there are stocks of wood, where you can take as much as you like to keep your fire going and when there is something like this, you don't have to worry about carrying your own firewood, which is very heavy, out into the forest. I have to say it takes some skills to get the fire going... or well in our case it took about 10 people with different Ideas and in the end I think our biggest help was the toilet paper roll we got from a restroom nearby! The fire make up such a nice atmosphere and when you grill some sausages or marshmallows over the fire the cold around you is forgotten. Sometimes there are also these little houses called "Grillkota" where you can go inside and make the fire there. It is much warmer, but you should always check if you have to rent it, because when you don't, it might happen that you just got a nice warm fire and then the people who reserved it are coming and claim the Grillkota... then you made the fire for someone else and it is very annoying, it happened to a friend of mine.
So when you have the chance to have a nice evening or afternoon at a fireside in Finland, grab your friends and some food and make a fire. It is definitely worth it!