Lead the kids in a play with hand puppets.
Study a book on Origami then teach it to the others.
You can make some bean bags (split peas in a ziplock bag, then a second ziplock bag to make sure they stay sealed. Practice juggling. Two kids two bags and play catch. Masking tape on the floor to make targets.
Find a library book on science experiments.
Have him develop art work to show the various kinds of clouds, the stages of an insects life, parts of a plant, the solar system, etc.
Draw the set for a scene from a movie or story.
Have him set up interviews to get statistics and do charts that show what he learned from the other kids. The topic could be: things you recycle, what you eat for breakfast, TV shows you watch or things that make you smile/laugh/cry or mad.
Give him flash cards to help other kids study the basics.
Class project to make 2013 calendars for Christmas presents.