There is such thing as creating your own games by using a program (but I am not really sure what's the name), but it can take some work.
But if you're talking about making one for the arcade here, it's impossible to make your own games for the arcade section. But the staff members do add the games for the arcade from the other websites.
I think there may be one of the programs to create games, such as Adobe Flash Player. I think I forgot to mention that.