Go for a walk.
Going for a walk whether it's in nature or in the city is a great thing to do to clear the mind, especially if you have been sitting at a desk or behind a computer for the majority of the day.
I see going for a walk similar to that of driving for enjoyment and to clear the mind, if that is the sole purpose of the activity. The difference between walking and driving is quite obvious I would hope, one requires you to move your muscles in a continuous motion in a given direction vs sitting behind a wheel doing similar movements to your work day (if desk work is what your day consists of). What driving does that walking does not however is that you can change your environment quickly, (emphasis on speed here) there is more stimuli to see and hear and the time between your starting point and your destination is shorter. Your visual and auditory experience of your drive can be enhanced by listening to some music or an audiobook, but then we have to ask the question, if the sole purpose of the drive was to "clear the mind" filling it with something may not be the best approach.
In contrast, what walking gives you can be more awe inspiring. A connection with the community and the people of the city streets can be found if one is open to looking a little deeper. Taking the time to pause and engage in conversation if the situation arises, just merely walking can do this. A connection to nature if your mindset is open to receiving the lessons of simplicity that are all around us. The sunlight and its path through the trees and hedges, the eclectic range of sounds that can be heard from the array of birds, the stillness of a tree and its roots anchored to the ground. Surrendering to life and letting things be, walking can help us to remain grateful for what we have and can remind us of what we strive to do, our purpose here is everything.
Go for a walk, it might just be the thing you need to continue.