The Sheila and her Dog Society is a Cambridge University society with the unusual distinction that it manages to get a bad reputation amongst freshers (new first years) before they've even unpacked and moved into their new rooms, entirely based on the description in the societies handbook that gets given out to them as they arrive. However, anyone that actually goes to a meeting usually realises that it's really rather good.
The basic purpose of the society is for everyone to meet up on Sunday evenings in their dressing gowns, ideally bringing their favourite cuddly toys and sweets, to read childrens' stories to each other in silly voices. Whilst the meeting is happening, no-one is allowed to swear or talk about adult things, for fear of having to 'unsay' them or have fluffy bunnies thrown at them. Recent books have included The Hobbit and the Harry Potter series.
The nature of the meetings means that most people assume the whole thing must be as dodgy as hell. However, it's more like a little island of calm within the permanent stress that is a Cambridge term. After the meetings officially finish, there's often an aftermath, involving activities such as midnight play park visits. Camping trips in the holidays have also been organised, as well as parties when everyone else has left town.
The society is incredibly liberal, and includes goths, MUD players, and lots of assassins (another society based on the idea of ambushing other assassins with water weapons to a level that induces extreme paranoia). If you're coming to Cambridge, or are already a student, it's worth checking out if you still secretly enjoy re-reading your old Roald Dahl collection.