Click on this:
Then you get to this screen:
Just fill out the form, putting your real year of birth and country
For the Class Code, type: "spmath906" without quotes. Then click join now and you should get a confirmation that you joined successfully. So click the tutpup logo to return to the homepage, and pick a category to start playing!
One last image to show you how fun this thing is:
I pick Celdrick to do the next scribepost.