hi you could do an Anatomy game, get the kids to face each other after you have told them the names of each bone in the skele and then use the whiteboard with all there (kids) names on and do a tally chart to see who has won.while your calling the names out the kids look at each other and you will see who is paying attension and who isnt. i used this for 14 yr olds when they visited the college i was lecturing at and it worked well and they thought it was fun.
quick and easy for you
regards
neil