Contrary to popular belief, you can rehearse improvisation on your own. Actually, if you're going to perform a Sybil, you'd better be rehearsing on your own! But, for anybody dedicated to improvisation, a little dash of improvising alone in the comfort of your bedroom (impubation?) can add some spice to your ensemble work, and can strengthen a variety of performance skills. This is not to say that, if you're part of an ensemble, that you should opt to rehearse exclusively on your own and then expect to slip easily into group mind onstage. Rather, these are good exercises to try out on your own as part of your improv workout - and they can be especially helpful if you are preparing a solo improv piece or if you are working to generate material for a one-person show

Solo Three Line Scenes
These will feel strange at first, but it's a great exercise to add to your warm-ups, as it gets your brain moving and gets you to commit fully to a range of characters. In character, initiate a scene with an opening line. Then, changing your physicality and even your physical position, Immediately switch to a contrasting character - the larger the contrast, the better, and deliver the second line of the scene.Then, move back into the original position, physicality and attitude of the first character and deliver the third line of the scene. For the first few of these, start off being easy on yourself, then tighten up the scenes. Focus on getting out the who, what and where in those scant three lines. Work through negative and dismissive responses until you are only giving yourself positive agreements with each three-line scene. Push your range of characters and your range of contrasts - you should keep doing these until you are well beyond your stock characters.

Solo Two Character Scenes/three character scenes
Once you have warmed up with three line scenes, slow down and try an extended two-character scene. Focus on giving gifts to yourself - "Rosemary, your pale gauntness is delicious!" Let these go a little long so that you can explore the possibilities of being the sole driver of a scene. As you slip between characters, let yourself be physically neutral. Take care to keep the characters' physicalities distinct. After a couple of these, challenge yourself to try three character and group scenes.

The Gauntlet
Set a clock for 10 minutes. Start with a character monolog. After no more than 60 seconds, you should slip into a two character scene with that character. From there, keep "cutting to" or wiping to related scenes, flashbacks, flashforwards, or completely new scenes. The two goals are a) to improvise nonstop for 10 minutes and b) to create as many characters and situations in 10 minutes as possible. Do one of these as a practice, and then do one for real. Let yourself be creative in your "cut-to" situations. This exercise strengthens an improvisor's sense of responsibility onstage - you quickly learn that you can't bail on a scene or check out mentally! It also builds your confidence, playfulness and your facility in being able to play and heighten a moment in a long form.