Upon first hearing Hatsune Miku's digitally generated singing voice, you either fell in love with the character, or you wanted to punch her in her virtual face.
For the latter group, Sega will be selling these Hatsune Miku Punching Bags at the upcoming Snow Miku 2012 event.
The cost to punch the virtual idol in the face is ¥2,000... plus air fare to Hokkaido, where Snow Miku is being held from February 6 through February 12.
Sega also has character charms, straps, clear files, a model of a Hatsune Miku ad truck, an airplane-shaped coin case, and other goodies for the event. Have a look at the items here. 4Gamer has pricing information if you must know.