As reported by engadget,
Amazon is making it easier to remember an event you don’t want to miss. The Verge reports that Amazon has quietly introduced a hinted-at “tell me when” Alexa command that not only answers your question about an event, but sets a reminder when that event happens. If you ask Alexa to “tell me when the Super Bowl is,” your Echo or a similar device will both answer the question (February 7th, 2021, for the record) and alert you that day.
You can also use “tell me when” for things like TV show air dates, holidays, or emails from contacts. The feature is only available for Alexa users in the US at present.