1. Suck water out of the carpet in your basement after it floods.
Can't really recommend this. For one thing, it's a very slow process, trying to vacuum water out of a carpet. And there's always rather a lot of water left in the carpet that you have to let air-dry, because the vac can't suck it up. But it will dry much faster if you vacuum most of the water out. Really. Much faster. Still, I'd have to recommend not having a basement that floods. Or, barring that, not putting carpet in your flood-prone basement.
2. Jury-rig to pump out water when your sump pump stops working unexpectedly.
A vacuum is not a pump. This is better than using a mop and pail while the water level rises, but still ... not fun.
3. Vacuuming up spiders.
Now this, on the other hand, is rather fun.
The spiders in my basement have taken ruthless advantage of the hospitality I had extended them. The truth is, I don't like spiders, or insects. They scare me. I realize I am much larger and more dangerous than your average spider or millipede, but they still freak me out. Last night, as I attempted to go out the basement door, I realized that it had been nearly webbed over by at least three different spiders. I retreated, and resolved to launch a counterattack the next day.
Tonight, I made my move.
"Lut .... "
All right, granted, my move was to ask Lut to kill the spiders. Still, I did the asking! That's action.
Lut went down stairs, un-jury-rigged the shop vac and reassembled it as a shop vac, and handed the end to me. "Go on. Vacuum them up."
The shop vac has many advantages over a paper towel or a rolled-up newspaper. For one, you never have to get your limbs anywhere near the spider. You reach out with the wand and -- shwoop! Into the vac the spider goes! If the spider tries to run, you follow it with the vac and -- shwoop! Want those spiderwebs gone, too? Shwoop! Shwoop!
After I was done vacuuming them up, Lut started back up the stairs. "Wait," I said.
"Wait for what?"
"What if they're not dead?"
"They're vacuumed up. Trust me, they're dead."
I look nervously at the shop vac.
"What do you want me to do? Open it up and reassemble spider parts to prove to you they're dead? 'I think this thorax goes with that abdomen'."
"I'll drown them." I open the now cleared basement door.
"The hose. Will you help me get the vac out so I can drain it outside when I'm done?"
So Lut wrestled the vac out the back door while I poured water down the vacuum hose.
You know how it goes.
Make sure the monster is dead.
Next to me, Lut is playing World of Warcraft. I glanced over. "What's that?"
Lut: "It was a spider." His character runs high along a hillside to avoid it. "However, I don't have a shop vac. That's why I'm running away from it."