Let me add my voice to those who've suggested paper/print as the medium of choice for this type of project. I teach digital preservation at a library school, and one of the key points we make to students is that while it is possible to preserve digital information in the long term, doing so requires a much more active curation of the information than is necessary with traditional printed material. You can leave a book on the shelf for 15 years and come back and reasonably expect to find the book in usable condition. You can't make that assumption with digital information. Format, software and hardware obsolescence all conspire to make digital information unreadable unless someone is actively working to combat them. Time capsules guarantee that you can't engage in the necessary curation of the data. If I was going to try to do a time capsule approach anyway, I'd probably say get a cheap laptop and put all of the data and software necessary to view it on there, seal it up in a ziploc bag with a packet of desiccant, and pray that the thing boots up after 16 years. That way, you only have to worry about the hardware dying. If it lives, you'll have a complete environment for examining the data.