Cosmo Chips is another free mediawiki template with a strange name 
It was adapted from the browser-side source of The Mono Project. Cosmo Chips mediawiki theme carries clean design, black, white & green colors, two columns and right sidebar. It can be an ideal design for your personal, single-user website. Download it and you won’t feel sorry.
MistyLook is an elegant mediawiki skin; its minimalist style along with simplicity, usability and pleasant-to-eye look will bring the theme more and more popularity. MistyLook mediawiki template was released on the basis of a wordpress theme developed by Sadish Bala. The author has put a lot of care and attention in it, and I believe you will like this free mediawiki template.
The Dusk skin was heavily influenced by the great WordPress theme by Becca Wei. It is a good blend of valid XHTML/CSS and twilight colors. To install the theme extract the files to your skin folder. Compatible with Mediawiki 1.6.
