e-Business Australia

Facebook hosts things like quizzes but entire games are largely handled by outside servers. Most games are hosted on their website in one group or another

There are in-facebook programs called Applications. Photos, Groups, Notes, etc. are built in default applications, but users can add more of their choice by going to the applications page. Developers make applications like games by using the facebook developer tools to write the code to make applications. In your question, users don’t upload games and applications, they just can show or hide certain applications on their profile page.