I recently stumbled across the Artstorm contest, be creative in 15 minutes! I like the idea and its a contest that fits in easier with work. Thanks 
Here's my entry:
The flowers are based on a photo I took of some apple tree blooms. I did a quick pencil sketch and then drew all the lines with different Crayola coloured pens. I wanted to add some more shading but lost my pink pen while drawing... :(