Avatars are a great way for students to 1.) share their personality and 2.) create a picture to represent themselves on the internet without using a real picture of themselves. There are many websites out there that can help your students create an avatar. I am not really looking at appropriateness or if these sites are blocked at school, so please do so before using these in your classroom.
Build Your Wild Self
Face Your Manga
Mr. Picasso Head
I did have examples from each of these sites, but I am having technical difficulties getting them on this post, so check back and maybe I will have fixed my problem.