GameOn World is a free geography game system developed by a teacher and his student here in Maine. GameOn World is played in a manner similar to Kahoot. The teacher projects the game questions on a screen and students reply from their phones, tablets, or laptops. One of the convenient features of GameOn World is that you don't have to create an account in order to start playing fun geography and history games with your students.
In the video embedded below I provide a demonstration of how GameOn World works. The video includes the teacher's perspective and the students' perspectives.