Okay, this isn’t a 5 minute exercise per se, but you could make it one. It would simply last for 10 days.
The idea is simple. Write a new “something” every day for 10 days. It’s inspirational, challenging, fun, and at the and you have 10 new pieces of work to choose from. Every time I have done this challenge I have come away with at least 4 new things worth polishing up. I encourage doing the challenge with other people.
If you don’t have a lot of time, you could do 5 minutes per day for 10 days focusing on a particular idea. For example, let’s say you needed to do some character development. Every day, for 10 days, write for 5 minutes starting with the line My Character is… (or My Character wants… needs… must…). I guarantee you will know a lot more about your character at the end of those 10 days.
My own past ten day challenges include:
*A short screenplay per day
*A poem per day
*A flash fiction story per day
*A short monologue per day.