Shooters is wordpress theme that suitable for blogs / sites with game niche.

Arcade Games Ready is a Simple gaming theme for gaming and arcade wp websites.

Action Games and WP Gaming is a free Excellent compressed gaming theme. Suitable for any niche especially for gaming related sites.

The Casino Magazine is a Free Wordpress themes. Suitable for any niche, especially for Gambling, casino, games niches.

New Angry Birds is a free simple two column WordPress theme. Suitable for any niche, especially for games niches.

Contrive is a free WordPress theme with options page. Supports the post thumbnails. Suitable for any niche especially for games, online games or entertainment sites or blogs.

Game Strike is a free WP theme based on Counter Strike. Ideal for a games blog. Includes the popular Nivo slider and logo PSD.

Angry Birds WordPress Theme is based on the popular Angry Birds theme created by Rovio. Includes jQuery Nivo Slider and PSD logo.

Dark Edition is a free two columns fixed width WP theme with grunge header, lavalamp menu and jQuery nivo slider, suitable for any niche.

An amazing modern Game wordpress theme, well documented (help file). of course this theme is free for download.