Two truths and a lie is the most consistently funny icebreaker in my repertoire. You can re-use it too, because people have to come up with a new material each time: a new lie about themselves and two new truths to hide it behind. It works best for small groups, by which I mean 5-7 people. It can stretch to groups of 8-10, but that can get time-consuming, and time pressure takes the fun out of this one.
The instructions are simple:
1. Ask everybody to write down 2 things that are true about themselves and one thing that is a lie.
2. Have one person read their list.
3. Ask the rest of the group to guess which is the lie.
4. Repeat steps 2 and 3 for each person in turn.
VARIATION: Have people write down and share 2 truths and a lie about someone else.