The one-minute rant is a great improv exercise for one person, and you can do it just about anywhere: while commuting to work, vacuuming, gardening. The sky’s the limit (though if you do it with other people around, they may look at you strangely).

Start by looking around you. Identify an object or word to use as inspiration, then go on a one-minute rant about that object, adopting a strong character/point of view. Keep going for a whole minute. Then, pick another word and start a new rant with a completely different character.

Example: A priest ranting about post-it's.