The word Improvisation.

http://en.wikipedia.org/wiki/Improvisation

Improvisation is the practice of acting, singing, talking and reacting, of making and creating, in the moment and in response to the stimulus of one's immediate environment and inner feelings. This can result in the invention of new thought patterns, new practices, new structures or symbols, and/or new ways to act. This invention cycle occurs most effectively when the practitioner has a thorough intuitive and technical understanding of the necessary skills and concerns within the improvised domain. Improvisation can be thought of as an "on the spot" or "off the cuff" spontaneous activity.

The skills of improvisation can apply to many different abilities or forms of communication and expression across all artistic, scientific, physical, cognitive, academic, and non-academic disciplines. For example, improvisation can make a significant contribution in music, cooking, presenting a speech, sales, personal or romantic relationships, sports, flower arranging, martial arts, psychotherapy, and much more.

Where the improvisation is intended to solve a problem on a temporary basis, the 'proper' solution being unavailable at the time, it may be known as a stop-gap. This particularly applies to engineering improvisations.

Musical improvisation
Main article: Musical Improvisation

Improvisation is usually defined as composing music while playing an instrument at the same time. In other words, the art of improvisation can be understood as composing music "on the fly". This of course requires great skill and knowledge, and is a very important aspect of music in general, for any experienced musician. Musical improvisers often understand the idiom of one or more musical styles—e.g. blues, rock, folk, jazz—and work within the idiom and music-theory of the certain style to express ideas with creativity and originality. Improvisation can take place as a solo performance, or interdependently in ensemble with other players. When done well, it often elicits gratifying emotional responses from the audience. Very few musicians have ever dared to offer fully improvised concerts such as the famous improvised piano recitals by classical composers/pianists like Franz Liszt. The origins of Liszt's improvisation in an earlier tradition of playing variations on a theme were mastered and epitomized by Mozart and Beethoven. However, some have managed some very poignant attempts similar to these precedents, one of the most successful of these is Keith Jarrett. He is a jazz pianist and multi-instrumentalist who has performed many completely improvised concerts that have captivated audiences all over the world. In the same creative aesthetic as such named masters, including the late innovator and guitar master Derek Bailey, comes a new breed of improvising musician. Pioneers like cellist Eugene Friesen have brought improvisation to traditionally classical instruments. A few pianists have given modern recitals of improvisation in the baroque style, which may be less intimidating because of its stricter development and range of modulation and yet, on the other hand, more daunting because of its polyphony. One of the masters in the style of baroque improvisation was Glenn Gould. There have also been a few other exceptional improvised solo piano concerts in Stuttgart, Southern Germany in the 1990s.