Hello @revitworkbench and @RobDraw,
I have the solution 
See the Dynamo script below and in the attachment.
just place it in the Daynamo player when you have Revit 2017.1

Below you see the Python Script:

********************************************************************************
import sys
sys.path.append(r"C:\Program Files (x86)\IronPython 2.7\Lib")
from datetime import datetime
now = datetime.now()
str_format = IN[0]
OUT = now.strftime(str_format)
# >>> 25-01-2017
********************************************************************************
See this link for the date and time format string parameters.
Just play with it.
Please let me know if this is your solution.
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Kind regards,
Robert Klempau
Senior Consultant AEC
Cadac Group AEC BV