There's some demo logins that you can use to play around here. They are: visitor1, visitor2, and visitor3. Each has a password of their name. One and two are in the 'visitors' group, three is in the 'tourists' and 'systems' group.
The following are some restricted-access pages that you can experiment with:
Of course all of this only works if I have turned on authentication in the server configuration. (You can tell by the presence of a login or logout box at the bottom of this page.)