For some great brain workouts, you should incorporate doing things with your non-dominant (usually left) hand into your everyday life.

Why Use Your Non-dominant Hand?
Well, because it let’s your brain struggle a little with coordination and doing a movement it isn’t used to.
And it comes with many benefits.
Such as less depression, better self-control, less stress and an increase in creative thinking (study).
Whould could have thought, right?
How To Incorportate Your Non-dominant Hand More?

If you think about it a bit, it becomes very easy to just use your left, or non-dominant, hand more throughout the day, until it becomes an ingrained habit.
Do it while brushing your teeth, when eating (fork or spoon in wrong hand), when washing yourself and so on.
This should make it fairly effortless even in the long run, and you can keep reaping its benefits to your brain.
And with that I leave it up to you to use your non-dominant hand more!
/Emil