On page 9 of this pdf you will find a couple of delightfully simple informal mindfulness exercises.
The first one is a mindful showering exercise. If you’re reading that, you’ll know you’re on the right page.
These are perfect for people who don’t want to commit to doing something everyday. You can use them whenever you need something restorative or need a boost of relaxation and centering.
Don’t overlook the part at the bottom of the page that refers to making up your own simple mindfulness routines (the example given is eating your first two bitefuls of food mindfully).