Firebox offers USB Snakescope camera
Almost falling into the NSFW category, Firebox is offering the USB "Snakescope" camera, a still slash video borescope for under £30.
With a "robust", semi-flexible insertion tube, the camera head and cable are waterproof, so ideal for checking out your, er, plumbing. There's also a clip-on magnet that will help to retrive metal objects.
Complete with software that allows you to view, edit and save down recordings, the snakescope records in VGA quality and works with Windows-based PCs.