Things to entertain myself at school?

Finals are coming up next week, so we are only doing reviews for finals in class. I am exempt from all of my finals, so for the past 2 days all I do is stare at walls. For some classes it is fine because I can talk to my friends, but I don't really talk to anyone in 3 classes because I either don't know anyone or I don't sit by my friends. So, I am looking for some creative ways to keep myself entertained without going overboard.

All I can think of is reading a book and playing on my phone, but I don't read often and I use my phone so often that it dies by the time I get out of school.