Is there any server side script available, that an administrator can run on the server side to update all the objects owners in an environment to a specific User?

Use case: Our environment has around 5000 objects with last modified date mentioning 8/20/2010 8:30 AM by A, 8/20/2010 8:30 AM by B... As the Users A, B are no longer exist, we need to update the object owners of those objects to a specific User(which we use for our Deployment).