It's extremely rare that I realize I'm dreaming. I can't actually recall it ever having happened before at all, though I think it may have once or twice. Twice last night I was aware that I was dreaming inside my dream. I wasn't sleeping well at all, and that might have had something to do with it. It was a strange experience.
I know it happened twice, but I only remember the first time it happened. I was watching a woman retrieve a makeup case from her purse, and I noticed that it looked an awful lot like the memory card reader that I bought recently. It even opened the same way that this reader expands and collapsed. I thought that was very strange, and then it hit me. I don't know how I knew, but I just did—the feeling reminded me of déjà vu, in that you feel like you've seen something before, but you don't know how or when or why. A few seconds after this realization hit me, though, I awoke.
It happened again later that night, in the same sort of situation. The dream included a coincidence that was apparently just too absurd for me to accept, and at that point I realized once more that I was dreaming, and then woke up.
Both times, upon waking up, I knew immediately what had happened, and my dreams were very clear to me for a few moments. I felt very strange... almost powerful, in a way. I had done something I may not have ever done before, and it was a bit surreal.