As you can tell I butchered the help file some . If you have popupmenus enabled the first item on the menu will be the vba macro that is in the Macro property. If the project is not loaded it will load, then executes. otherwise it executes macro. The popup name I used was "Try This" the macro was "HiYa".

[VBA]

Private Sub AcadDocument_BeginShortcutMenuDefault(ShortcutMenu As AutoCAD.IAcadPopupMenu)
' This example intercepts a shortcut menu start while you are in the default mode.
'
'MsgBox "You have just initiated a shortcut menu in default mode!"
Dim I As Integer
Dim MakeIt As Boolean
For I = ShortcutMenu.Count - 1 To 0 Step -1
If ShortcutMenu.Item(I).Caption = "Try This" Then
'ShortcutMenu.Item(I).Delete
'MakeIt = True
MakeIt = False
Else
MakeIt = True
End If
Next
If MakeIt Then
'ShortcutMenu.addMenuItem 0, "Try This", "-vbarun ""C:/Program Files/AutoCAD 2000i/Sample/VBA/tryforpopup.dvb""!ACADProject.ThisDrawing.HiYa "
ShortcutMenu.addMenuItem 0, "Try This", "-vbarun ACADProject.ThisDrawing.HiYa "
' syntax "-vbarun ""filelocation""!projectname.module.sub "
'if macro is loaded when this project is load ACADProject.ThisDrawing.HiYa is all tht is required
End If
End Sub
Private Sub AcadDocument_EndShortcutMenu(ShortcutMenu As IAcadPopupMenu)
'shortcutmenu.
' clean up so it is not left over
Dim I As Integer
For I = ShortcutMenu.Count - 1 To 0 Step -1
If ShortcutMenu.Item(I).Caption = "Try This" Then
ShortcutMenu.Item(I).Delete
End If
Next
End Sub


[/VBA]

Happy Coding