Getting a range of cells to act like radio buttons (True to revert to false if true in another cell)

JamFestival 

Data Validation limits what the user can enter in a cell, but it cannot change the value of a cell automatically. You need VBA for that.

Let's say the range is C2:C12.

Right-click the sheet tab.

Select 'View Code' from the context menu.
Copy the code listed below into the code window.
Close the Visual Basic Editor.
Save the workbook as a macro-enabled workbook (*.xlsm).
Make sure that you allow macros when you open it.
Code:

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim rng As Range
    If Not Intersect(Range("C2:C12"), Target) Is Nothing Then
        Set rng = Intersect(Range("C2:C12"), Target)(1)
        If rng.Value = True Then
            Application.ScreenUpdating = False
            Application.EnableEvents = False
            Range("C2:C12").Value = False
            rng.Value = True
            Application.EnableEvents = True
            Application.ScreenUpdating = True
        End If
    End If
End Sub