Patrick's Day Fun in the Classroom has great St. Patrick's Day ideas and resources that you can use in your second grade or third grade classroom. Includes crafts, reading, math and science St. Most of the resources are free!
A St. Patrick's Day hallway display of your students' faces as leprechauns. I love this idea! I would combine it with a creative writing assignment written inside a 4 leaf clover and glue the clovers beside these leprechaun faces.