FitNesse. UserGuide.
TodaysDate [add child]
To diplay todays date:

Markup Text
Displayed as
Today is !today. Today is 06 May, 2026.
XML is !today -xml. XML is 2026-05-06T07:11:39.
Right now it is !today -t. Right now it is 06 May, 2026 07:11.
Tomorrow is !today +1. Tomorrow is 07 May, 2026.
Last week was !today -7. Last week was 29 Apr, 2026.
The month is !today (MMM). The month is May.

As you can see, you can add or subtract days. You can include the time tiwh -t. And you can use your own format for the time. (See SimpleDataFormat for the syntax.)