Long time no see. I've stared doing some greyscale one brush sketches in Photoshop, I find it quiet fun and enjoyable. Here are a couple I've done at the coffee shop Ugly Mugs lately.
This first one was originally of the guy sitting in front of me with me trying to let on that I was trying to sketch him, then I decided to some some side and background, so it was entirely thought out, but it was my first free hand PS sketch, it was fun.
This next one is of Atomic Robo from the comic of the same name