Hey guys,
I noticed that this shop is missing some solenoids!!
What are they good for?
mm, let’s see! Here is one old example where someone is using a bunch of them to create music!! 
http://www.youtube.com/watch?v=g_hiz-Kx0kM
And here is one where they are used for a different type of graffiti
http://www.behance.net/gallery/txtBOMBER/406136
And here is a solenoid controlled by arduino:
http://www.youtube.com/watch?v=azZ3yuNLfj0&feature=related
I am waiting! I hope I find them in the shop soon! 
All the best,
ygr