What are your favorite 'one-off' themed attractions?

This is a great question and I could spend hours on it, but I'll throw two existing attractions out here, and then one extinct one.

As a kid in the '70s, I visited Lake George in upstate New York on a summer camp trip and there discovered the House of Frankenstein Wax Museum. It's a very cheesy walk-through with famous horror scenes and movie ghouls behind glass with some "audio-animatronics", if you can call them that. But it made a deep impression on this monster-loving kid and I continue to stop in when in the area, although I can't say the attraction has aged very well. Along the same lines, and far less well-known, is the Haunted Mansion in Kensington, Prince Edward Island. Someone turned a warehouse into a giant Tudor mansion that contains a horror walk-through, as well as a Dickensian village in the basement. The grounds have gardens, games, amusements, and a "train" ride. Worth a detour if you're on PEI.

But my favorite one-off attraction ever was a multimedia show in Manhattan called "The New York Experience", which ran from 1973 to 1989 and was housed in a sub-basement of the McGraw-Hill Building in Rockefeller Center. It was the longest-running commercial multimedia show in history. The show was 55-minutes long and it ran for more than 51,000 performances. I think I saw it on at least 2 different class day-trips into Manhattan (I grew up in the suburbs). It told the history of old and new New York using dozens of screens on which slides and movies from dozens of projectors were beamed. There were tons of (then-sophisticated) special lighting and audio effects, and at one point Nathan Hale's body fell from the ceiling when he was hanged by the British in 1776. In addition to history, it was all about modern New York, and even had a mugging scene! Bubble machines poured out bubbles at the end. I loved it and I miss it, but sadly it wasn't well-documented (you had to be there) and it's hard to find recordings or other information about it. I'd love a chance to see it again.

At Knoebels park in the Poconos in Pennsylvania,
They have an old merry go around where you have to reach for the ring.

They also have some bumper cars that are actually good bumper cars
They go fast just like in the old days.

It doesn’t quite count as you can consider it part of Hersheypark - but it is outside of the park gates - thus I’d say Chocolate World is quite fab.

I totally would count Hershey's Chocolate World as an outstanding "one off" attraction. I was frustrated that it *wasn't* part of Hersheypark - not even part of a combo ticket. But even the free part of Chocolate World - the dark ride - made it well worth a visit.

Here's my trip report for Hershey's Chocolate World, from a few years back.

I've been trying to come up with a good one here, but ultimately most 1-off attractions are nothing more than "tourist traps". We've typically only done ones that have been included in a CityPass or other combo admission, so have never experienced them as an a la carte attraction. We also tend to avoid one-off theme park style attractions, because it's not typically worth it to waste time on those with similar or better attractions at a nearby park that has a full day's worth of rides and shows.

I was impressed with One World Trade in NYC that turned the elevator trip to the top into a pretty cool multi-media experience. However, most of the other tall buildings we've done are pretty similar (didn't do the plexi-glass potato sack slide at the US Bank Tower in LA, but the Skydeck at the Willis Tower and clear floor at the CN Tower are comparable experiences). Obviously, the Stratsphere in Las Vegas is in a class of its own with actual theme park rides on the top of the tower. I also think the High Roller (the newer Ferris wheel, not the defunct roller coaster) is a pretty cool experience, though I'm a little biased since we've always done it with the unlimited bar.

Chocolate World is a good call, but I always associate it with Hersheypark since we've never visited and not done the theme park. Though I've never seen value in paying for the extra attractions beyond the free dark ride given that we would spend a full day in the park.

The Beatles Love show @ Las Vegas

TITANIC in Belfast, Northern Ireland. It’s so much more than the other Titanic exhibitions scattered around the US. It even includes a dark ride! It was fantastic.
The Guinness Store House, Jamesons distillery, in Dublin, Heineken exhibit in Amsterdam and Atlanta’s World of Coca-Cola are also terrific.

Obligatory link to our Guinness Storehouse trip report.

In Galveston, Texas, there's a Rainforest Cafe with a dark boat ride inside it. The animatronics are no better than the ones you'll find in the restaurant, but at $6 a ticket, it's a pretty good value compared to other smaller attractions.

Especially compared to the crappy Jurassic Jungle Boat Ride in Pigeon Forge at $15 per person.

Earlier this year I was able to visit the Shanghai Tower in... well, Shanghai. The tour kicks off with holographic displays of the tallest buildings in the world, along with physical models of the tower next to the Burj Khalifa. The elevator had a video presentation displaying the speed and ascent as we skyrocketed into the air, and the display deck windows point out various landmarks throughout the city and their sometimes shocking distance from the tower - one of the landmarks, clearly visible, was 23km away! Sure, it set me back $20, but I'd recommend it to anyone visiting Shanghai.

In Atlanta GA there is the Cyclorama - the permanent installation of a traveling painting depicting the battle of Atlanta during the Civil War. The painting itself was done sometime in the 1880s. It was closed to the public in 2015 and reopened in April 2019 in a new location and exhibit building. It's just amazing to look at the size of the painting and realize that this traveled around the US, by train and wagon, and was reconstructed at every stop for several years. While not "theme park" related this is definitely a "themed" exhibit complete with the Texas steam locomotive which was part of the Civil War locomotive chase which also involved the General. The Buster Keaton movie "The General" depicts that Steam Train Chase.

I was very impressed by Bird Kingdom on the Ontario side of Niagara Falls. Being right at the end of Rainbow Bridge in the country's biggest tourist town, one might expect somewhat of a tourist trap with little or no theming at all.
What I found was a very beautiful, fairly detailed multi-room experience with some Adventurer's Club type theming, that built up towards the big reveal of the main/largest room.
It was a great example of an attraction who's managers realized it was themed entertainment in the form of animal display rather than an animal display with theming added in.

I'll gladly second LJ's suggestion of The Cyclorama. I haven't seen it since the move and restoration from Grant Park to the Atlanta History Center, but it is a really amazing piece of art.

A Facebook friend just reminded me of the Star Trek Experience at the Las Vegas Hilton. That was really cool.

As it is "just a restaurant" (pancakes..) , one would not think about classifying it as an attraction, but it is !! WHAT is ?
It's themed in eating zones based on different (fairy tale) stories and other experiences such as an earthquake.. :-) Every zone is themed-and-animated.
More fun during eating your pancakes is difficult to imagine !
(Netherlands, Zeewolde)

And this video :
https://www.youtube.com/watch?v=awF4Q8EshOs