This person made a pencil or pen holder from old cassette tapes! Looks like he just glued them together maybe used a piece of cardboard for the bottom. We have so many old cassettes and not enough pen holders at the studio = ))
Real 3 inch computer hard drive converted into a desk clock with a quartz drive movement installed. The clock measures roughly x and runs on 1 AA battery. It's for sure the best gift for your favorite geek.