Senseboard is one facet of our using tangible media for manipulating abstract information. It allows the user to arrange small magnetic pucks on a grid, where each puck represents a piece of information to be organized, such as a message, file, bookmark, citation, presentation slide, movie scene, or newspaper story. As the user manipulates the physical puck, the corresponding digital information is projected onto the board. Special pucks may be placed on the board to execute commands or request additional information. We seek to combine the benefits of physical manipulation (natural, fluid, rapid, two-handed, multi-person interaction) with the benefits we can get from computer augmentation (interactive commands, functions, queries, operations, importing and exporting data, and remote collaboration). We believe this type of interface is thus more effective for tasks involving organizing, grouping, and manipulating types of information that have no inherent physical representation, and it provides an example of a tangible interface for a typical "knowledge worker" task.
(Source: http://tangible.media.mit.edu/projects/senseboard/)