I run a contest on Twitter at most all the conventions I attend now. People are invited to retweet the sketches I post at that con and at the end of the weekend, one random retweeter will receive a head sketch of the character of their choice.
This is what the winner of my New York Comic Con 2012 Sketch Retweet Contest chose: Battle Damaged Spider-Man
Next contest will be during Long Beach Comic Con Nov 3-4, 2012.
So follow me on Twitter: http://twitter.com/toddnauck
Drawn with Copic sketch marker and Pigma Micron markers.
Learn more about COPIC markers at http://affiliates.copicmarker.com//jrox.php?id=121