We did not rehearse at all together, and had no idea which roles our fellow company members were playing.  On the night of our performances, the audience yelled out a number that corresponded to different cast combinations, and it was revealed which part we were playing and who we were playing opposite.  Then we improvised the show, having prepared only the parts we were given.  This was a trip-  the best exercise in listening an actor could ever have AND wildly entertaining for the audience because (whenever mistakes were made) the stage manager kept us in line by honking a horn at us and getting us back on track.  Hilarity ensued.  

This is the final monologue during one of my stints as Kate.  
Enjoy!  (I know I did!)