LEGO is the greatest engineering platform. I have two projects in mind utilizing these wonderful toys. One of them is a CD/DVD duplicator arm. I want to create a device that does not rely on software to drive the arm mechanism creating a platform/software independent mechanism for delivering blank disks from a spindle to the CD/DVD drive and then pulling off the spent media. This mechanism can also be used for bulk ripping of my DVD collection. The action of the CD drawer opening will trigger the arm to pull the disk out of the drive, drop it on the spent media spindle, and then grab a fresh disk and put it in the drive. The arm will then trigger the button to close the disk drive.
The LEGO interlocking bricks come in handy for this task because they have adapter plates for servos, switches, and gears that can attach to standard LEGO bricks.. All the pieces are made to fit together and if you need something special, you can drill or melt a piece to do a custom job.