Once I woke up and didn’t get up from the bed, cause I thought I was tied to the bed with chains and a giant lock which was floating in the air 
A few days ago, I woke up at about 12:00 am and thought my alarm had gone off.
I went downstairs and got ready for the day, glancing at the clock occasionally, but not noticing what time it really was. After I was done getting dressed, I looked at the clock, reality checked, and then went back to sleep.
On the plus side, it felt like I got 4 more hours of sleep!
I’ve done several stupid things, for example I often get up and speak with whoever I meat (brothers/sisters/parents), without being aware of what I’m saying like some kind of sleepwalk. It’s usually jibberish without any context, so the person I’m talking with doesn’t understand what I’m saying - that’s when I often get mad thinking that the person is stupid.
It always ends with me going to bed and I rarely remember what I’ve done when I wake up for real. ^^
When I was little, I stood up, only half awake, walked across the room, turned the lights on and went to sleep again. On the next morning I wondered why the lights were turned on until I remembered it. A few years ago I went to the bathroom, fully awake and confident that it was already morning. I changed my clothes and was about to brush my teeth when my parents entered the room and told me that it was only midnight. I was so confused. 
Yes I have. It was a few weeks ago, when I had to get up at 6:30 because I needed to go to school early to catch up an technology work. When I went to sleep, my alarm clock was 9:45 and it was 9:45. When I got up, my alarm clock was ringing and it said 6:30. I then went to wake up my mom so she could get ready to drive me to school at 7:30. But she told me it was 4:30! I’m like “DOH!”. I think I must’ve accidentally pressed the set up button in my sleep to two hours of the real time…I then set my alarm to the correct time, then I went back to sleep.
I actually have a minor sleeping disorder that with work i manage to keep regulated pretty well. When i didn’t, i had a habit of sleep texting at odd hours of the night. But i actually miss doing that, my friends would reply confused or entertained at the wierd stuff my half-asleep self would come up with 
I woke up when a roommate opened the door. Then I turned the light on, said something the other one couldn’t understand and went back to sleep. I wasn’t able to remember anything of this on the next morning.
I once had a sort of false awakening where I was “woken up” by the fire alarm. So in the dream, I jumped out of bed and ran into the upstairs hallway. Then I woke up for real and did the same thing, except there was no actual fire alarm.
You know, I’m not actually scared of the fire alarm because I think it means there’s a fire (I have long ago figured out that it just likes to go off for no reason), but rather because I’m scared of the noise it makes. And it’s loud, too. . . . 