Updated: Sep 29, 2022
Are you a fan of IMAX? I've got some news for you. Are you asking yourself "what is IMAX"? Well, let's talk about it. IMAX has been around for over 50 years. It first started as a temporary experience - mostly for art. The first permanent IMAX theater opened in 1971 in Toronto and is still open today. In 1994, IMAX went public and built its first theater in NYC. Hollywood was not yet making these types of movies and wouldn't until there were more IMAX theaters. However, the founders couldn't open more IMAX theaters until more movies were made. What a pickle.
The founders, Graeme Ferguson and Roman Kroitor went on to create a new technology called Digital Re-mastering (DMR). It gave directors the chance to create these IMAX movies. The first movie that used this was Apollo 13. It was highly successful and Hollywood ran with it. 
There are several differences between IMAX movies and regular movies.
IMAX movies come with a larger screen and higher sound and picture quality. These screens are about 6x bigger than a standard movie theater screen.
The standard screen size is 16:9. The IMAX screen size is either 1.43:1 or 1.90:1 - it's large and curved.
The standard film size is 35mm (rectangle); the IMAX film size is 70mm (square). You see more with IMAX movies than on standard movies.
A few years ago, IMAX started offering private theaters. Their "Palais" package started at $400,000 and their "Platinum" package started at $1,000,000! These costs include their equipment (projectors, screens, chairs, lights, 3D glasses, media server, Blu-ray player, and touchscreen control) and installation. 
While searching about this, it appears the company no longer offers private IMAX-branded theaters. There are still ways you can get an IMAX experience, though. It's much more affordable and even more feasible.
If you're an avid movie watcher (mainly on Disney+ as of now), you may have noticed the IMAX ENHANCED tag. These are movies that have been remastered to show as IMAX movies. It's still very new and not many movies are made or remastered for this experience, so its specifications aren't consistent (screen size, black bars, sound, etc.).
However, if this is something that sounds interesting to you, there are products you can buy today that are IMAX Enhanced capable. These certified products include:
Sony BRAVIA XR OLED A80J (TV)
Hisense ULEF 4K U8G (TV)
Sony VPL-VW715ES (projector)
Polk Legend Series (loudspeaker)
Denon AVR X6700H (AV receiver)
And more! IMAX is partnered with more companies so it's likely more products are on their way.
A few of the movies that are IMAX Enhanced include:
And more with more to come.