I've had a few of these before. They're extremely rare for me, only occurring about once every two years or so, but when they occur, they're usually so vivid that they create an actual memory with pictures and everything that I can remember for years afterwards. I can still recall images from one of my past lucid dreams as clear as if I had the dream last night. Very interesting stuff, and yes, I remember actually being in the dream and interacting with it. Usually I start to really have detailed dreams approaching that during the time in the summer when I first get home and I'm not working, so I just sleep all the time, 8+ hours every night. At school, under stress and not getting enough sleep, I'm definitely not going to have any good dreams.