A very simple applet, requiring no coding and using the WolframAlpha(tm) website (not requiring the CAS).
After Show Info is pressed:
How it works:
label is a simple text label, the text in parentheses is the label's text
pickDate is a date picker object, in parentheses is how the picked date should be textually represented.
The function part of the object says under which name, date, the result should be accessible by other components.
Get Info is a button (everything that's not a special element is a button)
Its function is to call the given URL. $$ designates variable content and in parentheses is the variable (date) that will provide that content. That is, this part of the URL will be filled with the textual representation of the picked date we chose above.
When the user taps Get Info, the picked date is used to format a URL that is invoked and subsequently displayed. In this case, a WolframAlpha® page about a given date. The info there, then, tells you stuff about what happened on the picked date. (For example, anniversaries of important events or known people.)