I attended a musical improv workshop this evening. The class focused on melody, basic harmony, and singing in an operatic style. It was fun trying to make up songs in an operatic style and quite difficult to remember that in arias the lyrics are simple but are often decorated with various vocal flourishes. Recitative does get to have many more words, but it's not very melodic.
There was no focus on comedy but there was a lot of laughter during the evening. We had songs sung by Greek gods, songs about castles and lunch, and even madrigals. One of my favourite exercises involved songs sung to "la" which where then translated into English by one of the other improvisers. I also enjoyed the various exercises in harmony as I don't get to sing with groups that often and miss the beautiful sounds that are made by multiple voices.