Let's mix some grays and have fun!
Gray does not have to be boring... in fact, gray color can enhance any bright color. Get control of how to mix any color especially useful warm/cool neutrals. This video starts very basic and moves on to matching tubes of expensive grays that you can actually mix yourself.
I find that may students don't want to deal with boring blah gray paint. Color is much more exciting. Yet, students are always asking - how can I mix this color? This video will answer this question for you. Be sure to check out the Cityscapes collection of demos to use your new gray mixes.
Watercolor artists can use this video with water as white, and using Payne's Gray (or equivalent) for a challenge mix. For warm/cool basic explorations in chromatic gray use Burnt Umber and Cobalt or Ultramarine Blue.
Other media artists such as gouache or acrylic can use the same paints noted.
Challenge yourself to not be biased against drab gray and instead get out your paints and play.
The next step is to pick a gray scene. Cities and twilight/dawn scenes work well. So does moonlight. By understanding basic grayscale, and then shifting to warm/cool you should get some exciting results for your chosen project. Several videos in the program use gray. This video should break that down further for beginners, or those who like to follow step-by-step for mixes.
It's great to have ultimate control of value plus color... especially for larger paintings.