Setting Up A Guest User Account In OS X?
Setting up a guest account on Mountain Lion:


  
  Choose Apple menu > System Preferences, and then click Users &amp; Groups.
  Click the lock icon to unlock it, and then type an administrator name and password.
  Select Guest User in the list of accounts.
  To let a guest user log in to the computer, select “Allow guests to log in to this computer.”
  
  However, guest users can’t log in remotely.
  If you let guests log in, you can also set up parental controls for guests by selecting “Enable parental controls” and clicking Open Parental Controls.
  
  For more information about the limits you can set, see this help topic:
  
  Set up parental controls
  To let guests use your shared folders and their contents from another computer on your network, select “Allow guests to connect to shared folders.”