What's your question? You can put anything in there that evaluates to a string.
Reporter.reportevent, micPass,variableName","The current date is exported to excel"
That code looks a bit iffy (too many commas, too many quotation marks). How about this:
Reporter.reportevent micPass, variableName, "The current date is exported to excel"
Which is fine if you have already put the current date into variableName (your dynamic value that comes from a paramater). You can also add your own text by concatenating a string with your variable using an ampersand:
Reporter.reportevent micPass, "Date: " & variableName, "The current date is exported to excel"
"The last 10% of any software project will take 90% of the budgeted time. The first 90% will take the other 90%"