I've heard this called many things, but basically you get half the class to stand in a circle in the centre of the room facing outwards. Then the other half of the class form a circle round them, facing inwards. You shout a question and give them 1-2 minutes to discuss it. Then the outer circle students take a step to the left (the inner circle doesn't move) and find a new partner. Repeat. Or you could just let them find out as much as possible about each partner, without you shouting questions.
Pick a question
You need a pack of cards and a copy of the question sheet here for each group of 3-5 students. The students work in small groups of three or four. Students take it in turns to take a card, and answer the question that it corresponds to. For example, the King of Spades is "What was your favourite toy when you were a child?". A higher level class could work in groups to write their own questions. One group writes questions for hearts, another group does the diamonds questions and so on. Then you photocopy their questions and distribute them so each group has all the questions.
True or false
Demonstrate this by writing 3 - 5 sentences about yourself on the board, some true, some false. Encourage your students to ask you questions and guess which ones are false. Then they write their own sentences (you should monitor and help with any language issues). When they are ready, put them in small groups and they can tell the others their sentences. The others should guess which are true and which are false.
Demonstrate this by drawing a star on the board. At each point, write the answers to questions (as in the image here). Your students should guess what the questions might be (for example 'rats' could be "what is your favourite animal?" or "what are you frightened of?"). Then students make their own stars and guess each other's questions.
Find someone who ...
There are lots of these ready-made in books and on the internet, but students can make their own. Give each student five slips of paper and get them to write five sentences about themselves on them. Collect the sentences in a hat, then hand out five to each student. They must "find someone who" the sentence is true for. It doesn't matter if they get one of the sentences they wrote - in that case they should find someone else who is the same as them.
Find something in common
This is very straightforward. In small groups (pairs or threes) students have to find as many things as possible in common. You could give them topics to help them, such as family, hobbies, likes/hates, home, holidays, work. In feedback you might want to reinforce the use of "both/all of us" and "neither/none of us" to report the answers.