I had way too much fun with this thing! Comic Strip Generator was the first image generator I played around with and it is one of my favorites. This site can be used in the classroom for motivation and a fun way to present short facts. Students and teachers can make cartoon characters remind them of study habits, editing tips, etc! I bet it will sink in more if Homer is reminding my 4th graders to edit their papers than if I do. Another one of my favorite image generators is Image Chef. Even better than making cartoon characters say anything you want is taking your own picture and giving it a fun caption! It gives that personal touch. Students can use this site to introduce themselves to the class or present social studies material.
Librarians can use either of these tools to make reading more pleasurable. Students can upload images of books they've enjoyed, give it a caption, then hang it in the library on a "suggestions wall!"