Improv comedy is still alive and well in some large American cities. But it is not flourishing given the large number of scripted comedy shows on cable and network programs such as Saturday Night Live. If you are interested in improvisation and those who choose to devote themselves to mastering the craft, Don't Think Twice is the best movie around.

The Commune is a six-member Manhattan improv group that has been in existence for 11 years but now faces some immense challenges to its continuation. First and foremost is the fact that the small theater that they call home is being sold. Secondly, Jack (Keegan-Michael Key), a gifted member of the troupe, is asked to audition for a spot on Weekend Live, the premiere comedy show on TV. The group has always viewed themselves as collaborators, so now shock waves of envy, anger, and betrayal rumble through their hearts and minds.

Jack's live-in girlfriend Samantha (Gillian Jacobs), who also is invited to audition, skips the chance, preferring to not get caught up in the cut-throat world of celebrityhood. Miles (Mike Birbiglia), who teaches improv and sees himself as the founder of the Commune, is deeply hurt when his student gets the break instead of him. Bill (Chris Gethard), a shy actor, and Alison (Kate Micucci) a cartoonist, form a writing team but they don't get very far after having Jack submit their samples to the head writer at Weekend Live. Lindsay (Tami Sagher) is the only member of the troupe who has no financial worries since she has inherited money from her parents. She can afford not to live in a dingy apartment or work at tedious and low-paying day jobs.

"A good improviser is someone who is awake, not entirely self-focused, and moved by a desire to do something useful and give something back and who acts upon this impulse," writes Patricia Ryan Madson in Improv Wisdom. Her laws of improvisation include "don't prepare, act now, take care of each other, and enjoy the ride." The actors in the Commune would add "don't think twice." It is when they do and try to control their lives that things fall apart for them. Life is by nature uncertain, and improvisation has become a necessary survival skill in our times.

Don't Think Twice as a film is a mixed bag. One the positive side, it gives a rounded look at the challenges faced by those who choose this play-it-by-ear way of life. And on the negative side, the story reveals the toxic power of competition, envy, and regret as emotions which take all the pleasure out of both improv and community life.