Update that antiquated peephole with this $138 Brinno Digital Peephole Viewer. It's an LCD display with a tiny camera on the other end that fits into that cylinder now occupied by your current peephole. The company says it can be installed "in a matter of minutes," but we're thinking that depends on your mechanical ability and how difficult it might be to remove that existing peephole.
We like the way you can either peep in a normal view or zoom in for a closer look. The company says two AA batteries will give you 1,700 peeps, that is, if each look lasts the 10 seconds it takes until it's automatically turned off to conserve battery life.
Another benefit is the person at the door won't be able to tell if you're peeping or not, unlike old-fashioned peepholes that suddenly get darker when you're looking through them. It's available in Australia now, let's hope it finds its way Stateside. Attach a motion-sensitive peephole recorder, and you'll have a total security package.