Applying the Office 2007 theme to the Calendar can be accomplished with only a few lines of code. You also have the option to change the base color used in the theme. By default the color will be the same color blue as used in Office 2007.
'Create a new Office 2007 theme object Dim customOffice2007 As New CalendarThemeOffice2007
'set the base color for the Office 2007 theme to use 'This will give a default "gray" base color customOffice2007.BaseColor = RGB(22, 22, 22)
'Apply the Office 2007 theme to the Calendar CalendarControl.SetTheme customOffice2007