For those interested in history there is plenty of options to discover. Dolmens from pre history such as La Varde is worth a mention, as well as Occupation Museum, Underground German Hospital and many many more. There is a local dowsing group – www.guernseydowsers.co.uk
Then there is the Napoleonic history and, for example Castel Cornet – lots of stories there from the time of Roundheads and Cavaliers, and of course the Second World War. The Channel Islands was the only part of the UK to be occupied and Alderney was a concentration camp. There are Museums and fortifications and the Underground hospital.
If you like music, there is live music from Baroque to Pop to Folk – look at the Fermain Tavern, and the Doghouse, and the Cock and Bull Pub. Classical and other concerts at St James Concert Hall – a converted church. There is a brilliant music service in the schools and young musicians from all over the world attend ECSOC – Elizabeth College Summer Orchestral Course, which lasts a week and culminates in concerts at St James. In the Summer there are Sunday afternoon concerts by the bandstand at Candie Museum, and evening Castel Cornet for people to picnic and then wander round enjoying a variety of different music.
Guernsey was the inspiration for the book and now film The Guernsey Literary and Potato Peel Pie Society. You can often go on tours of the places mentioned.