Received this goodie from my 'way much older' brother, who just had yet another birthday and who is likely planning something with this I do not want to know about. The site LINK allows you to send a free email message to yourself in the future. You can also send an email to others, but have to set up a free account to do so.
You can post-date it for anytime in the future, weeks, months, years. Might be fun to get something back that you were thinking now or planning for the future to remind yourself of the plan. . . and answer for it. It cautions to not use work email addresses, lest you change jobs.
The site has many copies of emails that others have sent and allowed the site to post. It has also made a book of some of the emails. Great fun and might honestly answer the question, "How did that work out for you?"