Until now I always assumed it was something vaguely sexual. It is often used on the darker side of the internet, hence the misunderstanding. I never bothered to actually find out until now.
Turns out it’s the perfectly innocent badum-ching sound…
If you’ll just show me the way to the exit I’ll be going.
Rimshot is used on the darker side of the internet?
I’d assume you’ve found out by now, but what you were thinking of is rim job.
“Rim shot” and “rim job” are not the same thing. It is good that you learned this now, instead of when you are in bed with a beautiful woman and breathily ask her if she would give you a rim shot, only to hear her say in a confused voice, “Ba-dum-ching?”
And all along I’ve thought that a rim shot was a basketball shot that bounced off of the hoop’s metal rim…
The “I fail at life” should be followed by this.
Good thing, otherwise they’d be pretty painful. And they wouldn’t sound like much.
It would make going to comedy clubs far more interesting, though.
So that’s what a rimshot is. I’d seen the term used by Dave Barry, but I didn’t know what it meant.
Do I fail at life, too? (And I don’t even wanna know about rim jobs).
You all know, of course, that it’s only a matter of time before body shots, rim jobs, and rim shots all coalesce into something that’s probably a lot closer to what the OP had in mind.
If you mean that it bounces off the front of the rim without going in, that’s a “brick”.
In case you get curious, it’s a
rusty trombone played in monotone.
Instant rimshot included a link to
http://www.headsethotties.com/
which is exactly what it says it is. Clearly, there is now a website for everything.
But “snow job” and “blow job” are the same, right? I hope so… I use them interchangeably all the time. 
No, they’re the opposite. One involves the accumulation of snow in your driveway, the other involves the removal of it.
I also read the term in Dave Barry books for years before figuring out what it meant. I did get, from context, that it was associated with a one-liner joke, but I figured it was related to the basketball term. Like, it was a joke that didn’t quite hit the mark.
I also thought for years that it was a basketball term. (I know almost nothing about basketball, so there must be plenty of basketball terms I’ve never heard in their original context.) Since “rimshot” was always used after corny/obvious jokes, I too figured it was meant as an acknowledgment that the humorist had gone for a joke but not quite managed a truly funny one.