FUD Zilla spotted Intel researchers came up with a way to reuse old servers and cluster them in such a way as to turn them into data center routers:
The boffins, Gianluca Iannaccone and Sylvia Ratnasamy, have developed what they call “router bricks" for the reused servers which should save cash for IT departments. At the heart of the system is an open source software package called Click Router, developed at MIT a decade ago. This ties the servers together for their new roles in the data center.
The main reason this can be done is because of Intel's multi-core Nehalem chips, which provide the bandwidth and gigbit speed for these router bricks to perform at enterprise levels.