I just came across this super fun amusement park themed science game through Google+. It's called Nanospace from Molecularium and the premise is simple. Learn and demonstrate your knowledge of science through games. Educator resources for Molecularium can be found on this page. I played one of the games in the waterpark and it demonstrated how the atoms move around in water at different temperatures. Even though it wasn't hard for me to figure out, it was very engaging and I wanted to keep playing. If you are a science teacher, I would definitely check it out. If kids latch on to it, you can use it as a reward if they do their work. If you do use it, let me know what they think!
I had a teacher ask me if there was a way to hide or remove students who are no longer in your class. The answer is maybe. It depends on if they are officially dropped from your class and appearing as red in your roster and gradebook. If not, then no, you cannot remove them until they have been unenrolled from the class. If the student is showing up as red in your gradebook though, you can hide them so you don't have to worry about them. Here is a screenshot to help you do it: