Our Pre-K class made a very basic craft, but WOW does it brighten up an area.
You will need:
green construction paper
strip of black construction paper
I don't have any patterns here, I took the picture when I stopped in, but forgot to bring materials home to show the steps.
Draw a leprechaun hat shape on green paper. Have the children cut it out. Add the black strip and yellow shamrock for detail. Finally glue some streamers to the bottom of the hat.
This is one easy way to liven up any area for St. Patrick's Day.