The sketch comedy of "Saturday Night Live" grew from the mostly Second City Chicago cast of the early years, and many Second City actors brought on board over the years.
Improvisation as therapy or training has existed since long before there were any improvisational companies...dating back to the early days of Chicago's Hull House and the multi-cultural communication needs at the turn of the 19th to 20th centuries.
Improvisation has a proud history, a proud purpose and is of value to teachers, business leaders, actors and performers in all aspects of life.
Improvisation can be useful in developing the flexibility, sense of humor, and ability to accomplish things in business, church, with the family and other aspects of life. Listening skills, patience, the ability to change course and consider new options are all skills used and polished in improvisational workouts.
Improvisation is "acting in the moment." There are no scripts involved and no time to practice, rehearse, or memorize lines. Every movement, word, etc, is created in response to what is going on in an actor's immediate environment. It is often considered the most difficult form of acting because of the spontaneity involved. It takes a really skilled actor to perform it successfully. Improvisation, or Improv, classes are great for actors looking to challenge themselves, invent new thought patterns, and learn ways to act and speak in the spur of the moment.
Improv is creating a real situation and in doing so bringing up the emotions we all fee, including sadness as well as happiness, drama as well as comedy. Many comedy troops and even a form of night club entertainment have evolved with the sole purpose of making audiences laugh. Some use full character development and scene structure, others may not.
It is best to become a part of an ensemble. If the students are not the same from class to class or if there is too wide a range in ages, walk away. The goal is to get to know and read your partners, which takes time and a group working through the entire course content as a group.
When you learn how to react to an unexpected situation without hesitation, you can save a play, or scene, or create an unforeseen nuance that betters the value of the entire project. Improv teaches you how to listen and react as opposed to just waiting for your turn to speak your lines. Your take in film, on television and even in commercials may be greater than the intended shot, and may remain in the script or in final edit consideration. In addition a greater number of producers and directors are relying on actors skills at improvisation to bring their story to life.
The tools of character, the five W's (who, what, when, where, why and how), scene structure, crafting a "reality' for the audience, the suspension of disbelief and all of the skills of an experienced actor come into play in impov, just as they do in other areas and styles of the art.
Over time, with more improvisation practice, an actor will get to a point where they can act with a wide range of options that best fit the situation. Improv training gives the actor the ability to read a script and see hundreds of different ways it could be acted out. Directors love an actor's ability to be malleable with their take on a role. This allows them to try different things with a scene to see what works best.
On a note of caution. There are many improv groups, improv "teachers", improv games and improvisation workshops. Most are not taught by professionally improv artist.
There are several "schools" of improv technique and execution. The Groundlings in LA are comedy centered and very different in focus than the first professional improv troop, Second City Chicago (where story, local politics and local personalities dominate the scenes and improvisations). Theater Games in San Francisco differ from London's West End (think 'Whose line is is anyway?").
You should learn the basics and move on to what is right for you, your talents, your personality and your approach. Remember even the most serious drama can benefit from basic improv skills, as can presentations of everyday life and your approach to everyday situations or problems). Remember also that improvisation can and will help in developing the flexiblity and adapatability needed in most aspects of life.