There are two types of Christmas gifts. OK, I’ll pause here while you all relieve yourselves of your favorite “there are two types of x” jokes.

Done? Good. Moving on.

On one side we have this:

What is it? It’s a USB powered aquarium, and it’s awesome. Consider that it’s entertaining to watch, demonstrates some pretty impressive engineering, and demonstrates two unrelated areas of physics.

Really? Yup. Let’s break that down.

Two principles of physics – Fluid Dynamics: there’s a fan inside that swirls the water, causing the fish to swim around. Consider the possibilities for discussion here: vortices, the interaction of moving bodies, edge effects. Light and Color: those cheery red and yellow fish change color. Well, actually, only the yellow one changes. Turn off the blue LED light, and the yellow fish turns green! (Very Christmasy.) Think of the hours of fun you could have explaining to a child–or a cow-orker–why one fish changes and the other doesn’t. Or why school says that blue + yellow = green, not green + blue = yellow. Or why blue + green = brown for crayons, but yellow for fish.

Impressive engineering – Yeah, seriously. This thing can run on USB or batteries. It feels solidly constructed: I have no worries about it leaking on my desk; the battery and water compartment covers fit securely, but are not so tight that it requires a fight to open them; and it doesn’t wobble or deform in my hand when I pick it up. The water fan and the light are on separate switches, so they can be turned on and off independently. Really, the only strange thing I’ve found in its design is that it requires a somewhat rare A-A USB cable instead of the more common A-B microUSB or miniUSB cable. But the necessary cable is included and is quite long enough to allow significant freedom in placing the aquarium.

Entertaining to watch – Well, I think so, anyway. The fish move largely in calm, counter-clockwise circles. Up, over, down, back, up, over, down, back… It’s quite mesmerizing to the predator part of the brain. I haven’t tried it out on the cats yet, but I’m willing to bet they’ll be just as entertained as I am. Up, over, back, down…

Now, consider that you get all that goodness for less that twenty bucks. (That’s an assumption based on rules of the gift exchange. Hang on a second… OK, yeah, I just did a quick search, and the median price online seems to be around $14.) The price-to-performance ratio on this thing absolutely rules.

Awesome gift, Eric. Nice job.

So that’s one kind of Christmas gift. Then there’s the other.

Those of you with weak hearts–or weak stomachs–may want to skip ahead here. The next chunk of this post includes some fairly graphic and fairly disgusting imagery.

Imagine the pain of being punched in the lower back. Repeatedly. In the same spot. Got it? Now add the pain of a live mouse trying to dig a tunnel out of your stomach. Add nausea, and flip a coin to see if it includes vomiting. Flip another coin for the possibility of diarrhea. Imagine that going on for four hours on a Friday afternoon. It’s going to pretty much kill any chance of clearing your desk before the holiday weekend.

That, my friends, is a kidney stone, and it is the sort of Christmas gift from Mother Nature that proves she’s a mean bitch with a sick sense of humor.

In my case, everything went away after about four hours. I felt OK Friday night and perfectly fine for most of Saturday. Sunday, around 3 in the morning, it all came back and did not go away. This led to a whole slew of exciting events:

• A call to the 24 hour nurse hotline
• An ambulence ride to the emergency room. (“This street is blocked by construction. Let’s try the next one over. Nope, that’s no good. What if we go around to the other side? Hey, this one is under construction too!”)
• A series of tubes connected to my arm (Oh, look! My own personal Internet!)
• A shot of some morphine derivative. Aah, blessed poppies that give relief from pain.
• A CAT scan (Ooh, here I go, into the Time Donut. [Actually, given the size of the hole relative to the size of the “bread”, “Time Bagel” might be more appropriate.] And out of the Bagel. And in again. And back out. Hey, it works! The Time Bagel sent me a good ten minutes forward in time!)
• A seven block walk to the drug store–in my slippers–to fill prescriptions for pain-killer and anti-nausea medications, followed by a 20 minute cab ride home while waiting for the pills to kick in. (Kudos to both the Walgreens pharmacist who filled the prescriptions quickly and the Friendly Cab driver who did not feel obligated to make conversation or crank the radio to eleven.)
• Arguing with my doctor to get a prescription refill so I would have enough pain pills to last until my appointment.
• Peeing through a filter to capture the stones when they finally passed.
• Constipation and gas.

For almost three days, I survived on a diet of pain pills, anti-nausea meds, water, clementine oranges, and herbal tea (not much taste, but at least it didn’t taste like plain water).

When we went to refill the prescriptions, we discussed the possibility of getting me a human-sized Cone o’ Shame to keep me from biting back at the damned stomach mice, but decided against it, on the grounds that I’m not flexible enough to get my teeth anywhere within three feet of my own stomach. Nice thick mittens might not be a bad idea in these circumstances, though.

Wednesday afternoon and evening, I captured several itty-bitty brown specks in the pee-filters. Joy! By dinner time, I felt well enough to have some Seussian Christmas roast beast, though it took a couple of additional days for my appetite to get back to normal.

By Friday morning, when I finally was able to see a doctor, my only remaining symptoms were the constipation and gas, which led to the final thrilling experience of the affair. I got to be a human pop gun! The solid waste backed up in my gut was quite solid indeed. It organized itself in a series of hard pellets, each separated from the next by a pocket of compressed gas. Once things started moving, it turned the bathroom into quite the shooting range. Pop! Tzing! Sploosh! (pause) Pop! Tzing, tzing, crash! Whoops, there goes the light bulb! (pause) Pop! Tzing! You get the idea. Picture a good ten minutes of this scene as all-natural pellets bounce off the porcelain and ricochet around the room trailing a high-pitched “whizzing” noise and a cloud of organically-grown propellent.

Great way to spend the holidays, huh? And I was lucky! I only had about four days of the really awful part (waiting for the stones to pass). It could have been up to four weeks and/or required some form of intervention. Zapping stones with ultrasound or lasers sounds cool, but I’d prefer not to experience either one, thanks. Still less interested in any of the more invasive techniques. If you’re feeling brave, you can check out some of the thrilling possibilities–with pictures, even.

I don’t even get to keep the stones as a trophy: they’ve been sent off to a lab for analysis, so I can look forward to making dietary and lifestyle changes to reduce the odds of recurrence. Not that they would really make great trophies. I did mention that they were itty-bitty. Again, lucky. Kidney stones have been reported as large as golf balls. Picture that. Better yet, don’t picture that.

And hey, statistically speaking, there’s a 5-10% chance that you, the person reading this, will at some point in your life develop kidney stones (though your odds are about three times worse if you’re male than female). “Worse”? “Better”? Make that “three times greater”. Good luck!

Sucky gift, Mother Nature. Lousy job.