Notion is a tiling, tabbed window manager for the X window system. Features include:
* Workspaces: each workspace has its own tiling
* Multihead: the mod_xinerama plugin provides very nice dual-monitor support
* RandR: mod_xrandr picks up changes in the xrandr configuration without the need for restarting Notion (read this, though)
* Extensibility: Notion can be extended with lua scripts. Browse through the scripts collection