There is no specific date type so you'll have to do a bit of error checking. Here is one idea of how to get a date from a user:
Dim dateString As String, TheDate As Date
Dim valid As Boolean: valid = True
Do
dateString = Application.InputBox("Enter A Date: ")
If IsDate(dateString) Then
TheDate = DateValue(dateString)
valid = True
Else
MsgBox "Invalid date"
valid = False
End If
Loop Until valid = True