emastic is an interesting looking CSS Framework that is designed for both fixed and fluid layout. It looks like a nice alternative to fluid layouts than YUI Grids, with simpler and more flexible column structuring and class naming.
* Lightweight (compressed weight less then 4kb)
* Personalized width of the page in (em,px,%)
* Use of fixed and fluid columns in the grid.
* Elastic Layout with "em"s
Blueprint is going to have to catch up and produce a version for fluid layouts.