My apologies. I definitely did not get enough sleep last night. I misread calculator as calendar.
I am not aware of a calculator control. I have no doubt there is one or more out there, though.
I found a nice form once upon a time. I probably have it saved at home, but am at work now. I think it was written by Dev Ashish (sp?). Not certain of that, though.
For that matter, I cannot now remember if it was a form or an ActiveX control.
A web search should do the trick for you.
