I'm guessing this is for checking customers in and out of a hotel and you want to force your users to get the dates right?
You could set the field up to Auto Enter a 'Creation' date or maybe a 'Modification' date.
On your layout, edit the the field to a 'Drop-down Calendar' so that the user can simply pick the relevant date if it needs to be changed...
Get ( CurrentDate )
In an unstored calculation field (not a date field with an auto-entered calculation), will return the system clock's date.
Wow, unstored it and it made all the difference. Thank you so much.