Classroom activity - Would I Lie To You?

Just a quick entry about a classroom activity I trialled today and worked well - I've called it 'would I lie to you?'after the BBC TV programme.
This activity works best at intermediate level and above, although I used it with an E3 group, who are actually a good pre-intermediate level, and can be used as a way of writing present perfect sentences and asking questions in past simple to elicit further information.
Procedure:
Teacher writes something on the board about themselves, e.g. 'I have written a novel'. Tell the students that they must ask a question to get more information. Put students in pairs/groups, and get them to brainstorm questions. They must then decide which question would be the best to ask, and , of course, ask it. The aim is to produce questions using past dime, but monitor and allow questions in other tenses if appropriate, e.g. 'How much money have you made?', as one of my students came up with :)
Place the students into groups of four, and tell them that they must now write down something about themselves that no-one else in the room knows. Make sure they use ' I have....' Or 'I have never....' Model some sentences if necessary, e.g. 'I have met The Queen' or 'I have never learned to ride a bike'. Students write down their secret on a piece of paper, and share it with their group. The teacher then collects the secrets, and distributes them to another group.
The groups must then decide a question for each secret to ask to get more information. Teacher monitors to help/ suggest etc. The groups then ask each member of the other group the same question, and decide which person is telling the truth. If they guess correctly, they get a point. It is then the other group's turn.
This was a fun activity, and very good for consolidating tense use, although some students found it difficult at first to make up a story - however, by the end, they became extremely inventive!