I'm currently two weeks into a 13-week beginner's ballroom dance course, which runs for an hour every Sunday from 1530hrs at Balanssi Studios within the Cable Factory at Ruoholahti. Lovely couple that run it - Matti and Tea - whose contact details are on their website at
http://www.mattitea.com
So far we've done some basic Waltz, Cha Cha and Samba
Despite being taught in Finnish, I don't find the language barrier a problem as it is all quite visual and the instructors often summarise a key point with a line of English during the lesson. Only 80 Euros for the 13 weeks - represents good value. They run these courses throughout the year and also offer individual classes for those wanting them on midweek evenings.