Sub round_robin()
Dim c() As Variant, u() As Variant, flg As Byte
Dim i As Long, j As Long, n As Long
n = 12 'change to 20 or whatever as you like
If n Mod 2 = 1 Then n = n + 1: flg = 1
ReDim c(1 To n, 1 To n / 2 + 1), u(1 To n)
For i = 1 To n - 1
If flg = 1 Then u(n) = "bye" Else u(n) = n
For j = 1 To n - 1
u(j) = i + j - 1
If u(j) > n - 1 Then u(j) = u(j) - n + 1
Next j
For j = 1 To n / 2
c(i, j + 1) = u(j) & " vs " & u(n - j + 1)
Next j
c(i, 1) = "PLAY " & i
Next i
Range("A1").Resize(n - 1, n / 2 + 1) = c
End Sub