What's the Oldest Piece of Technology You Still Use Today?

I'm sure many of you have ancient, obsolete gadgets kicking around your home, maybe gathering dust in the back of a closet somewhere. You know, that old Mac Plus you didn't have the heart to throw away or an old cassette Walkman in the back of a junk drawer somewhere. But how many of you still use on a regular basis a gadget that the rest of the world considers to be an antique? Do you still do your taxes on an old Tandy? Will someone have to pry your Diamond Rio from your cold, dead hands? Send us a picture! We want to see your still-in-use devices from yesteryear. Send pictures to contests@gizmodo.com with the subject line of "old tech" and I'll post a gallery of the best and most amusing submissions next week.