There is a lot of research being done in dream control, particularly in the areas of lucid dreaming and dream incubation. Lucid dreaming is a learned skill and occurs when you are dreaming, you realize you are dreaming and you are able to then control what happens in your dream -- all while you're still asleep.
Being able to control your dreams would be a very cool thing to be able to do, but it is a difficult skill that usually takes special training. It is estimated that fewer than 100,000 people in the United States have the ability to have lucid dreams.
Although lucid dreaming is mentioned throughout history, it was not until 1959 at Johann Wolfgang Goethe University that an effective technique for inducing lucid dreams was developed, and true research into the phenomenon began taking place. In 1989, Paul Tholey, a German dream researcher who had been involved in the research at that university, wrote a paper about a technique he was studying to induce lucid dreams. It was called the reflection technique, and it involved asking yourself throughout the day if you were awake or dreaming. More research has indicated the need to practice recognizing odd occurrences, or dream signs, that would be a sign that "this is a dream" rather than reality.
Stephen LaBerge of Stanford University, founder of The Lucidity Institute, Lynne Levitan and other current dream researchers have studied lucid dreaming techniques extensively. They refer to a technique similar to Tholey's reflection method that they call "reality testing." This technique and one called MILD (Mnemonic Induction of Lucid Dreams) have been among the most successful techniques for lucid dreaming.
The MILD technique involves similar reminders to the reality testing method but focuses those reminders at night rather than throughout the day and night. MILD begins with telling yourself when you go to bed that you'll remember your dreams. You then focus your attention on recognizing when you are dreaming and remembering that it is a dream. Then, you focus on reentering a recent dream and looking for clues that it is indeed a dream. You imagine what you would like to do within that dream. For example, you may want to fly, so you imagine yourself flying within that dream. You repeat these last two steps (recognizing when you're dreaming and reentering a dream) until you go to sleep. Using this technique, Dr. LaBerge has been able to have lucid dreams at will. Because this type of technique takes such mental training, however, LaBerge is now doing research using external stimuli to induce lucid dreams.