People don’t really bother with time capsules anymore nowadays. If you like the idea but can’t make yourself go through all the hassles of putting one together, then you might want to opt for the easier alternative: ThrowBack.
It’s an iOS app that’ll let you take a picture and store it for future viewing. You can choose to have the app send the photo to you or to others after a certain period of time, from one month to five years. The image won’t be stored on your phone, but on the app’s servers somewhere on the interwebs, so it’ll arrive as a neat little surprise on the scheduled date that you’ve chosen.
The ThrowBack app can be downloaded from the iTunes App Store for free.