We've seen lots of crazy things on display at the Museum of Modern Art -- a "rain room," a sex toy that works with your phone, a sleeping Academy Award-winning actress. Now you can add "tablet app" to that list. Bjork's "Biophilia," an interactive album released on iOS and Android, has become the first downloadable app to join MoMA's permanent collection. First released in 2011 (and still available for sale), the album allows listeners to "contribute" to songs by playing with interactive on-screen visuals. In "Solstice," for instance (pictured above), the orbits actually allow you to control the string music, with the option to save and record your own version. Ultimately, it was that interactivity that earned the app a spot in the collection. "With Biophilia, Björk truly innovated the way people experience music by letting them participate in performing and making the music and visuals, rather than just listening passively," said MoMA senior curator Paola Antonelli in a blog post.