Daily Sketch Forum
http://www.cgtalk.com/forumdisplay.php?f=130

Artistic Anatomy and Figurative Art Forum
http://www.cgtalk.com/forumdisplay.php?f=177

Bobby Chiu's Subway Sketch Groups
http://www.cgtalk.com/showthread.php?t=247487

Speedpaints
http://www.cgtalk.com/showthread.php?t=18932