Saturday is International Towel Day, and you can celebrate it in sfnal company at least in Helsinki and Turku.
In Turku, your destination for Towel Day is Cosmic Comic Cafe where there will be theme-appropriate program from 6 PM onwards. At 6, there will be a "One Man Rush Hour", and starting at 9, you will be exposed to the worst poetry in the universe. At midnight those whose intestines haven't strangled them yet can participate in the creepiest laughter in the galaxy competition. For survivors, music until the prophet Zarquon (or the closing time) arrives.
In Helsinki, you can participate in the traditional Dirk Gently's Holistic Picnic which starts at the railway station (under the departing local trains sign) at 2 PM. Bring money, the Helsinki timetable, salted peanuts and a towel. The target of the picnic will be decided by flipism. More info: 050 534 7747/Vesa Sisättö.
I haven't heard of Towel Day–specific events in Tampere (please let me know if there are any!) but as a consolation sfnal activity on Saturday you can visit Suomalainen Kirjakauppa at 2 PM to hear Saara Henriksson talk about the ecological sf anthology Huomenna tuulet voimistuvat.