DarkMood
The DarkMood Theme is a free dark greenish theme 980px wide with two Sidebars and an Option Page to populate the Footer.
Expressivo
Expressivo is a three-column theme with two righthand sidebars – going to a single sidebar on single posts and pages. With Cufon embedded fonts for post titles, threaded and paged comments – you can also replace the header completely with your own image.
Bright Light
Bright Light is a two columns, fluid width WordPress theme with support for custom top navigation. It also has built-in support for social icons.
5 Grunge WordPress Themes
Themes are a little bit dark, a little bit dirty, and very grungy. Widget-ready and gravatar-enabled
