Let's compile a list of various types of reality checks we use.
If you're new to lucid dreaming or its terminology, "reality checks" (RCs) are things you do to help distinguish waking life from the dream world. While it may see obvious that you are wide awake right now, are you really? Think about it. Can you honestly tell me that at this very moment you are not dreaming? If you think you can, consider what happens in normal dreams. The most unreal and outrageous things happen and we think nothing of them. We accept it as normal.
Many of us have even had dreams in which we teach others about lucid dreaming and still don't become lucid. I had an LD once where I taught basic lucid dreaming principles to a group of people. But, I've had way more NON-lucid dreams in which I told people about LDing, RCs and related topics yet never even have it occur to me that I might actually be dreaming at that very moment. I even lied to a dream character once and told him that I was doing a reality check just to get on the subject so I could spread the word about this fantastic phenomena. Little did I know. Now much effort would it have been to just do the RC I lied about doing?
So, never assume that you are awake. You might be surprised at what your true state is if only to take a moment to test it. Any time anything even slightly out of the ordinary happens: if you see some one you haven't seen in years, if a weird car passes you, if a bird falls from the sky right in front of you (I actually had a dead bird fall from the sky right in front of me once. I wasn't dreaming though) try to remember to RC. Any time you experience a change of scenery, such as walking into a store or the sky becomes overcast... Pretty much anything could be a trigger to tell us that something may be out of place, unusual or awry.
When we dream, our default mentality is to accept everything that happens as normal, without any thought or question. When is the last time you saw a one-legged elephant prancing down the street sporting a halter top and Hitler moustache? Never. In real life, that is. But weird stuff like that is status quo in our dreams. The good news is that you can train yourself to take notice of such anomalies and turn them into triggers for lucidity. That's why it's of great benefit to practice doing RCs during the day.
Even sometimes when we know we are dreaming we still find it of help to perform an RC, just to make sure or to take the notion to the next level. The dreaming mind is not only easily fooled, but it can be very forgetful. We may know for sure that we're within a dream yet, the very next moment we may question our state or suddenly become oblivious to our condition. Am I really dreaming? Am I still dreaming? Am I dreaming at all?
Well, there's a way to discover if we are dreaming or not. Simply having reflective thought and being aware often isn't enough to make the call. That's where RCs come in. When you "check your reality", you want to do some sort of mental or physical task that can only be done in dreams. For example, flying. If you try to make yourself take flight and actually do lift off then it's a pretty safe bet that you are dreaming. Once you know you are dreaming then the fun can begin.
One quick note first: NEVER do anything dangerous, stupid or embarrassing as a reality check. Only take risks after you have confirmed yourself to be dreaming. The worst way to discover that you are actually awake is to leap from a second story window or get flattened by a truck. Use your common sense.
Most of my personal RCs are mental in nature rather than physically doing something. Here's a few of the RCs I like to use.
1) Ask yourself "Am I dreaming?" This is one of the most basic forms of RCing. But mere words won't do much for you. When you ask yourself if you're dreaming you have to mean it. Actually try to determine if you are dreaming. Look around. Are there any anomalies in your surroundings? How did you get where you are? Are people around you doing strange or impossible things?
2) "Nose RC". This is one of the most common RCs as well. Hold your nose pinched closed with your index finger and thumb. If you can still breathe fine then you must be dreaming. This one can be done nowhere. Unless you walk around holding your nose all day no one will think anything of it. You can make it look like you're scratching your nose or holding off a sneeze.
3) Finger through palm. Try to push a finger through your palm. I use an index finger and the opposite palm. Some people make a fist and try for same hand finger/palm. Whatever is more suited for the situation or your preference.
4) Try to float. I don't do this one too often but I've gone through spells of regular usage. Simply put, try to make yourself float or rise by thought alone.
5) Affect your surroundings. Mentally will something around you to move or change color, size, etc., and there's a good chance that it will... if you are dreaming.
6) Text/numbers. Written characters often tend to be unstable and elusive in dreams. Look twice at a sign or pages of a book. Does it change from viewing to viewing? Does it evade the direct gaze? Are the characters stable or hard to make out? Do they change to hieroglyphics? We are often fooled by text in dreams. We may be reading, say, a topic on Mortal Mist and everything seems just fine. But, are we really reading? A brief look away may reveal what we least expect: that we are dreaming. Don't assume that because you are reading something that you must be awake. A lot of times when we read in dreams we aren't reading at all. We're staring at lines and shapes on a page, sure. But many times we are really only tacitly knowing what is "written" instead of actually "reading" what is there. Upon closer inspection (or I should say, under conscious scrutiny *) the truth may come to light.
7) Clocks. This is especially valid with digital clocks. For some reason, just like with text, the average Human mind has a hard time creating a consistent image. Some number segments may be dim or missing. The segments may form illegible characters. The time may change completely from glance to glance. Actually, all technology seems to behave strangely in dreams much of the time.
8 ) Looking at your hand. Strangely enough, one's own hands and feet can present themselves in very strange ways during dreams. The may be hard to see, some digits may be too long or shaped oddly. There may be too many or too few digits. Looking at your hands is an easy RC to do in public. You don't have to walk around holding your hand in front of your face. Just kind of look down and see it and notice its appearance.
* NOTE: I emphasized "conscious scrutiny" to draw attention to a case of dream control, by the way. That is, doing something with conscious volition in a dream. Interestingly enough, it's completely possible to exercise dream control but not be aware that you are dreaming. That's where RCs can nudge you into lucidity. I thought I'd throw in that little aside since we rarely talk about or recognise dream control as a being separate - yet related - skill and "entity" from dreaming lucidly.
There are also times when you think you might be dreaming but just need that extra push to know or confirm that you are. It is true that "if you think you are dreaming then you are dreaming", in most cases at least. But suspecting isn't always the same as knowing. However, any time you suspect in the least that you might be dreaming, take the time to do an RC. I can't tell you how many golden opportunities I've missed by being too self conscious, busy or embarrassed to do an RC.
Sometimes I've been almost positive that I was dreaming but got caught up in the dream and allowed myself to be swept away instead of becoming lucid. "I don't have time to RC right now. They are waiting for me." RCs don't 'take time'. If you suspect in the least - or even wonder - just do it.
You don't want to walk around looking like you're not right in the head so choose the right RC for the situation you're in. It's amazing how - once you get into the habit of periodic RCing (randomly and when something prompts you to) - you sometimes discover yourself to be dreaming when you least expect it.
If you make it habit to RC on a regular basis then you'll be more prepared and likely to do so when you really are dreaming. And that's where the payoff resides. Now answer me again: Are you dreaming?
Please add you own favorites and feel free to comment on any already. The more ideas we can get the better.