I have created an online chemistry game, url: http://www.chemgametutor.com. The game can be used to help students practice essential skills in chemistry in a number of ways. The game is designed or high school students taking intro chemistry. There are currently 6 complete levels with 6 more being built. Teachers can open free accounts then allow their students to log in before they play. Their scores are then recorded for teacher review. It is sort of like students performing really fun worksheets in a computer game environment and only their best score being recorded for the teacher to review without grading anything. You need to check it out and explored for yourself. Any questions or if you would like to set up a free teacher account email firstname.lastname@example.org.