Get out with a camera and find as many examples of symmetry as possible. Then come back and classify them into how many lines of symmetry.
The quest can have points based on the number of lines of symmetry found. There are some really good sorting apps for phones see the whole thing on
Juliet Robertson blog
http://creativestarlearning.co.uk/maths-outdoors/investigating-symmetry-outdoors-using-photo-booth/
makingpi 