tours
There are several tours of the Old Town during the summer, most available in Swedish, but occasionally in other languages, and they are sometimes available for group bookings. The best bet is to check with the Tourist Centre Skeppsbron 4-6, 62157 Visby what guides are available in your language. Also ask whether you need to get a ticket before the tour starts or if you pay when you meet up.
Classic Tour of Visby (http://www.gotland.info/l...) Available in English, German and Swedish.
Sexualiteten i den medeltida staden (http://www.gotland.info/s...) Available only in Swedish. Adults 100SEK, Children 9-12 years 50SEK.
other events and activities
Boda Borg (http://www.bodaborg.com) Fun and challenging quests for people of all ages.