What you need:

autumn leaves
white paper A4
Crayons: red, yellow, orange, brown, possibly green as an addition
scissors
pegs

How to do it:

Ask ESL students to bring some autumn leaves in
Talk about their colours and other colours of autumn
Let the children choose two coloured crayons
Give out the papers and explain how to rub leaves to get a butterfly shape on their paper
When they finished rubbing the leaves, let them cut it
Finally put the peg in the middle

Hang the butterflies from the ceiling and enjoy having a nice autumny ESL classroom!!!