Superhero-genic spiders excepted, most of us like to keep a healthy distance from anything emitting radiation. In fact, things emitting radiation are pretty much the reason for the phrase "healthy distance." With that in mind, here are some common household items you may not realize are actually radioactive.

Bananas
No kidding. America's favorite phallic fruit is radioactive. Not because of scheming agribusiness, but because of the very potassium that makes bananas so healthy. About 0.01 percent of potassium takes the form of K-40, a radioactive isotope. Is it any coincidence then that bananas are favored by cyclists and that Lance Armstrong got cancer? Yes it is, you insensitive bastard.

Kitty litter
There's a lot of naturally occurring radioactive stuff in the ground, which anything coming out of the ground -- granite and clay for instance -- has a good chance of containing in trace amounts. Kitty litter's mostly clay, though the likely reason it gets singled out isn't the clay at all, but the cat. That's right, it's not the litter you should fear, but the remains of Captain Squishy-Face's last tuna dinner. The early '90s boasted two separate incidents of tripped radiation alarms at local dumps (heh) being traced to bags of used kitty litter. The kitties in question had ingested iodine-181 as a cancer treatment and were, uh, excreting radiation.


Ceramics
Not only is uranium useful for blowing things up and spawning city-hating giant lizards, it also makes an excellent pigment for pottery. Aficionados among you will already know that it's most famously found in the glazes of Fiesta Ware, particularly Fiesta Red. But uranium is all over the place in ceramics -- mostly, for reasons that would seem obvious, pre-World War II. Yet some companies still used it as recently as the 1970s, the lesson learned by Mothra evidently lost on the manufacturers of dinner plates, bathroom tiles and dentures.


Lantern mantles
Remember those old camping lantern mantles that were so fun to touch because they instantly disintegrated into dust? Well, hopefully you didn't inhale any of that dust. I'm just saying.


Watches
Contrary to the sci-fi cliché embedded like an alien in the thorax of our collective consciousness, radioactive substances don't glow in the dark. But combine, say, radium with a phosphor and paint it onto a watch dial and you've got a super-cool watch that glows basically forever -- unlike those lame ones that have to sit under a light for an hour to glow for ten minutes. You've also got a potent source of radiation strapped to your body, so if you have one of these antiques (radium was phased out by the 1960s) then do yourself and your future flipper-babies a favor and keep it away from your testicles. These days perma-glowing watches use tritium, whose weak beta particles can't make it past the watch glass. Same with night sites for guns, which use tiny glass vials of tritium gas to make the dots in which you line up your perp.


Smoke detectors
Turns out you don't fight fire with fire, you fight it with radiation. The alpha particles emitted by americum are an integral part of the ionization chamber used in many smoke detectors. These particles are too weak to penetrate glass, skin, or even more than a few inches of air, so unless you're foolish enough to disassemble a hundred smoke detectors for your homemade neutron gun, have no fear.


Your mom
Like all God's critters, your mom contains a lot of Carbon, 0.0000000001 percent of which is radioactive carbon-14. She's not going to be spiking any Geiger counters, but still -- your mom's radioactive.


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