We run the session similar to a pub quiz, reading questions from a book. We separate into 2 or 3 teams, depending on attendance. We could have more teams if we got more members.  At present we have 8 or 9 members at a session.  One of the group acts as question master and each team 
writes down their answers. The answer sheets are then exchanged for marking. The group is informal and we have a lot of laughs as we are not genii. (Plural of genius?  My Latin is almost non existent now.)  We can accommodate more people and would love some extra folk to boost our numbers.