This is something I did for the local drawing meet up I've been going to. The meet up has a weekly theme (for this one it was Floral Fantasy), and we meet at a cafe near Bryant Park. We do 40 minutes thumbnail sketches, pause and discuss our ideas, then take roughtly 2 hours to do a bigger drawing as finished as possible before we stop and tell each other about what we did. I liked this sketch enough that eventually I colored it and explored the idea some more.
Here is the news page for that drawing meet up group: https://www.facebook.com/groups/ImaginativeIllustratorsNYC