Anyone who enjoyed American Splendor would be well-advised to check out 1994's "Crumb". The film, although a documentary, is filmed in much the same style as American Splendor, or more than likely American Splendor is filmed in much the same style as Crumb. Irrergardless, it is a must-see.
Harvey Crumb was the avant-garde artist behind American Splendor, and frankly the documentary film is disturbing, hilarious and goes into great depth to explain the psychologically troubled pen behind the pages of American Splendor.