So, I thinkg "stuck" has to be defined further because I would imagine everyone at some point has had the 1-10 minute "stuck" due to load/unload issues that cauase the omnimovers to stop (HM, SSE, Mermaid, etc.). I certianly have numerous times.
The only true"stuck" I'd say for me was Space Mountain 1983. And, yes, while 32 years ago it was that memorable. We had just been sent on to the launch tunnel when we were stopped in that section right before you turn up the lift hill. It's the area with the flashing blue lights that are made to look like they're moving forward. We got stuck in that tunnel for about 45 minutes with the blue lights flashing away. They sent a cast member to come stand with us and talk to us (or keep an eye on us in reality).
Ultimately, they ended up sending every car through one at a time. Simply release each car from it's break location (so some were trapped in the ride part way through). Because we were in the launch tunnel we were the last or 2nd to last car allowed to go while we waited for every car to get to go before us.
BEST PART: We got to go through Space Mountain with all of the lights ON!! I'll never forget it. They also immediately took us back to the front of the line to let us ride it normal, but getting to see it with the lights on was absolutely awesome.
Having been to WDW numerous times, I now actually hope for cool experiences like that.