Okay, you're shooting outside and, for whatever reason, you don't have a set of lights, and you forgot your reflector! Don't sweat it. Here's a few quick techniques for exterior shots without extra lighting:

1) Exterior with Snow.
If there's snow on the ground, you already have a really good reflector. Just turn the subject to the appropriate angle. This also works in varying degrees with water (rivers, ponds, lakes) and some other white/whitish surfaces including sand, cement, some dirts, etc - but most of these surfaces are not as reflective as snow/water, so time of day and position of subject play a lot more into the factor.

2) Exterior in the woods.
You're shooting in the woods? Excellent. You can get some really good shots in the woods, since you are more in control of the shade around you (you don't always need to add light, sometimes subtracting light works just as good!). Just be sure to put the subject with his/her back towards the location of the Sun (but not in direct Sunlight, as this may be overpowering). Start removing bright _object_s until your shot looks properly lit. Many times a beam of light will hit in the middle of a shot (due to walking, or wind), but take it all in stride - the beam may help to sell the shot, but then again, it may detract. You're are the sole judge, so it's your decision Mr/Ms Director of Photography!

3) Exterior in the grass.
Well, so far - none of these are extremely hard. Set the shot up so that the camera is not getting too much sky. Face the subject away from the Sun, so that the light on their back separates them from their background. You may want to face the subject so that some of the light moves across his/her face - but that really depends on where the Sun is and what kind of shot you are looking for.

4) Need a little extra punch for a closeup?
How about using a copy of the _script_? Hold it under the subjects face to bounce some of that light and remove the shadows. What?! You forgot the _script_ too?!?! Okay, don't worry - this is where wearing WHITE is better than wearing black. If you have a white jacket, or even a white shirt, then it's time to show everyone that you come prepared...

All in all, you can shoot without lights and reflectors (the Cinéma Vérité crowd have been doing it for years with a very strict set of rules), but going without lights is a study in spartan techniques. Remember though, you still need to make sure you are getting quality images, since you are not only judged by your viewers, but also by your peers...