Well, not collaborating on music (yet), but on an article in USA Today expressing their dissatisfaction with Pandora. The article itself didn't really perk my interest at first, until I noticed that it was credited to Waters, Gilmour and Mason.
So, the three remaining members are playing nice? Great news! It's also a funny coincidence that earlier today I also stumbled upon an article reporting that the remaining members are secretly working on an album together, and planning a world tour in 2014. But, after nearly having a panic attack of joy, I realized that the article was definitely fake.
Here's the link to the USA Today article: Click here
And if you're really bored, the fake article: Click here