With the macro below you can toggle the availability of the Workbook Menu Bar, the Standard toolbar and a custom CommandBar. The first time you run the macro the menu and Standard bar are disabled, the custom toolbar is enabled. The next time you run the macro the menu and the Standard bar are enabled, the custom CommandBar is disabled.

Sub ToggleCommandBars()
Dim cbEnabled As Boolean
    ' get the current commandbar state
    cbEnabled = Not Application.CommandBars(1).Enabled
    ' apply the new state to the Workbook Menu Bar
    Application.CommandBars(1).Enabled = cbEnabled
    ' apply the new state to the Standard toolbar
    Application.CommandBars("StandardOPE").Enabled = cbEnabled
    ' apply the new state to a custom commandbar (the oposite of the previous two)
    Application.CommandBars("MyCustomCommandBar").Enabled = Not cbEnabled
End Sub