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

Markup Text
Displayed as
Today is !today. Today is 10 May, 2025.
XML is !today -xml. XML is 2025-05-10T05:38:33.
Right now it is !today -t. Right now it is 10 May, 2025 05:38.
Tomorrow is !today +1. Tomorrow is 11 May, 2025.
Last week was !today -7. Last week was 03 May, 2025.
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.)