no code yet, have looked on forum and found a lot of help with it. Dont remeber the site but there is one that leads you thru making the calendar and other stuff. I dont think it ever said if could be used for multiple cells.
here is an example of how you can have popup in just 6 cells
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Count > 1 Or Intersect(Target, Range("A5,A10,B3:B6")) Is Nothing Then Exit Sub
Private Sub popup_calendar()
MsgBox "popup", 0, ""
TO INSTALL IN SHEET CODE WINDOW:
1. right click the "Name Tab" of sheet you want code to work in
2. Select "View Code" in drop down menu
3. VBE window will open ... paste code in and exit VBE