Rockstar
If you are one of the numerous Guitar Hero fanatics, you will love this extremely tiny and cheap $15 Guitar Hero Carabiner. Now you can hone your rock star skills while commuting and annoy more people than just your neighbours.

The 7.75- x 3-inch device features a minuscule LCD screen, integrated speaker, five colorful buttons and a loop for clipping it onto whatever you want. Additionally, the neck itself collapses down to make the guitar just 4- x 3-inches for easy portability.