They're Nendoroids, they come with 3 interchangeable faces along with a blank face that you can put stickers on to make your own expression! Rin comes with a microphone and Len has a guitar keyboard. I bought them from my friend but you can find them on many websites such as Amazon, Ebay, and toystoreinc.
They get pretty pricey though.
Here's Rin on Amazon, but she's $225.00! O_o [link]
They also make Miku, Kaito, Luka, Miku Append, and Snow Miku.
Gumi and Gakupo are in the works! Hope that helped!