How have I not written about Vappu? A friend of ours who escorted us downtown last Saturday to see the sights of Vappu said it so well - something like: "all winter long you can feel like you're the only person who lives in this town. Then on Vappu the whole city is out on the streets and you see you weren't alone after all."
Go ahead and have a read about Vappu on Wikipedia. My layman's explanation of Vappu would be this: on the day (30 April), go downtown, put on your white (or yellowed, depending on how old you are) high school graduation cap at the appointed time, toast your friends and family right there with the alcoholic beverage you brought with you, parade down Aurakatu, then plop down on the grass for a picnic and people-watching and stay out as long as you dare (uni students in particular dare to stay out all night). I realize this is simplistic, but since it's my first year here, I think I'm allowed to be a semi-informed foreigner.
Clueless though I may have been, I loved Vappu. I loved being out and about in the newly sunny weather - it had snowed that Monday but warmed up to +16C by Saturday the 30th. I loved that the students were dressed up in their colored overalls and that even the very elderly still had their graduation caps. I loved really feeling the end of winter and realizing that I'm not the only one who lives in this city after all.