E-mail you in the future
Time capsules are fun to reflect back on a time in your life something occurred; most people will do it in high school or on their wedding day. There are various forms of time capsules, some put memorable items they treasure within a box and bury it to have it dug up later in life to reminisce.
Others choose to create video time capsules or letters and since we are in a digital age it would be ideal to receive an e-mail from yourself in the future, and since we seem to hang onto our e-mail addresses forever this seems like an ideal option to recapture a moment in time or to send yourself some encouragement.