I play a diatonic accordian…same kind as Flaco Jiminez of tejano fame. Shown here, solo begins at 2:45. Flaco does it a little better than I do. Kind of a useless skill, but unique in that they are not widely played.
SS
I can speak in a truly bizzare Donald Duck-esque voice. It was a hit when I was a kid but now, not so much.
I can talk like Kermit the Frog and dance like Yosemite Sam.
I can talk and have my lips/mouth move very differently from what I’m saying, like in a dubbed movie. I can do it better than anybody I have every seen on TV (not that that many people have done it).
Oh, me too 
Knowing how to use the right bait is very helpful
I can find stuff. It is actually a useful work skill because I can find a document lost in 18000 boxes of documents.
Its really handy for my friends. When Tony calls me and says that he lost his glasses I can tell him where he put them. Today, M called me and during the call, mentioned that he had misplaced his keys. I told him to look in the veggy drawer in his fridge because he had bought coffee and that’s where he keeps it. I am the goddess of finding things
Kinky I can understand Japanese that is way too far advanced to my skills. I can’t speak it well, but when a patient was having cataract surgery and started talking about how the bombs looked as they were falling, I understood her better than her daughter.
Oh, and I can knit chain maile. That’s about the most worthless skill in the working world.
I can do the voices for Kermit the Frog and Rowlf pretty well. I assume I could probably do most of Henson’s puppets decent, which I find surprising since my speaking voice and his aren’t similar and I can’t do any other impressions well at all.
Sad fact: I discovered I could imitate Rowlf while singing along to Tom Waits.
Whistling a reed of grass between my thumbs, making an empty common garden snail shell whistle. Ok, those two could possibly be useful at some point. Tug o’ war with tarantulas - a particular grass is needed … oh dear - how useless is that?
I do a lot of canning, and I have an uncanny (ha!) ability to look at a pile of produce to be pickled, pot of jam to be put up, etc., and to get out exactly the right number of jars for it.
I can also look at an array of food trucks and stands (at a music festival, etc.) and pick out the best one immediately. Everybody always says that what I got looks better than what they got.
Really good at the game Taboo. I don’t have any idea why, but I really kick ass at that game. Mr. Foxfyre and I as a team are pretty weirdly impressive sometimes.
MFF: “I didn’t even have to use my AK”
Me: “Ice Cube!”
Everyone else in the room: 
:smack:
Yo, you SPEAK J?? Git over here! We need J-speaking feral cat trappers!
And while I’m very impressed that you understood the patient’s Japanese, I’m kinda more impressed with someone who can start talking about events that happened some 60 years ago *as she’s having cataract surgery. * Unless it’s like LASIK, aren’t most people under anesthesia for that kind of surgery? You did well, luv, but I think the old lady won that round! 
Under 30 seconds here, still pretty useless though lol
None of these skills sound very useless. I am going to have a big party and invite all of you guys to come be weirdly skillful! We’ll take it on the road!
I can talk like a Speak & Spell, Stephen Hawking’s voice synth, etc.
I can also do pretty good vocal impressions of several of my coworkers. Always funny when I do one of them, and another coworker will laugh and say “Oh, you should do stand up comedy!” Because there’d be nothing more popular than a comedian who is imitating non-famous people.
I’ve begun speed-solving NYT crosswords. I’m not good enough for competition, but I’ve had small crowds gather around the table when I’m doing them on campus.
I’m pretty good at forming and blowing little tiny spit bubbles off of my tongue, sending them off to float away until they pop. I tend to only do it when utterly bored… and yes, I do realize it’s a very gross habit. But I’m good at it!
I’m good at spotting aircraft in movies and pointing out how said flick is using the wrong type for that era or the incorrect markings & color scheme. Same goes for U.S. Army field jackets & other types of uniforms pre-1960s.
Bri2k
I’m narrowly regarded as an expert on position players pitching in baseball’s modern era.
(Motto: No, Rick Ankiel Doesn’t Count)
I know how to jimmy locks, which comes in very handy when you work in an older building where half the keys to filing cabinets, closets, etc. are missing and someone locks them accidentally.
I’m also good at cards, especially pitch, gin, and 21. I can count cards in blackjack, but only with a single deck.
I’m full of useless skills:
I can recognize virtually any artist I’ve heard even just once or twice within a second or two, often even with a single note, based only on the production and tone.
I remember maps, locations, and strategies for video games I haven’t played in years, often even games I only played once more than a decade ago. Though I suppose that’s sort of an extension of my natural sense of direction.
I’m really good at little puzzles like the ones where you have to get a piece out/off (eg, Hanayama) or a Rubik’s Cube. I can solve a Rubik’s Cube in about 25-30s at my best, probably even 5-10s faster if I had a speed cube, but I’m rusty these days, so more like a 60-90s now.
I cannot remember any useful information (like names, numbers, dates) but I remember all kinds of worthless things particularly worthless trivia where I’m not even sure how I know it. I can usually interject on just about any subject with some random factoid, but I’ve learned to stop doing that.
I can twiddle my thumbs in opposite directions.
Pregnancy seems to have destroyed my best useless talent. I can open any jar or bottle, or at least I could before I became a baby pod. I hope I get the talent back after the kid is born cause it was a pretty cool parlor trick to be able to open pretty much anything with a screw on lid.