I was dreaming that I was in a swimming competition, doing the backstroke. For some reason, my right arm wouldn't extend properly out of the water. I was in the lead but the guy in the next lane was catching up. One stroke away from the wall and with him almost catching me, I gave my right arm a full lunge, and my wrist slammed into the bed's headboard. I'd been lying on my right arm, which is why I couldn't complete the arm swing.
On another occasion, I was in that short period just before dozing off. I was lying on my stomach and my knees were bent with my feet in the air. Knowing the danger I was in, I told myself to bring my feet down. Too late: my right leg fell outwards and I twisted my knee. Yes, I twisted my knee while lying in bed.
This one happened when I was a wee lad of about 8 or 9. We had an Alsatian who liked sleeping next to me when I went to bed. On this particular night, I climbed under the blankets and felt something move against my foot. I sat up in the dark and reached down, and felt the dog lying on my bed, facing the wall. I stroked her back and then lay down, my hand swinging over the side of the bed. And that hand brushed against the dog as she lay on the floor beside me. There was no way she could have jumped off the bed without me noticing. I sat up and reached down past my foot, but there was nothing there. Weird!