GUYS! We already basically know the concept for WA, but what about DU?
I was thinking like a dark style of video and dancing like Can't Be Tamed, the oversized and flamboyant decorations like California Gurls, with Tim-Burton esque costumes. It'd be like weird people in a dystopian underground city coming to life at night, with whacky coloured hair and stalkings. And they rebel against their queen and eventually win.
It'd be like three scenes. It'd start out with the queen (evil Katy) petting her cat, singing the beginning of the song, then she hands it to one of guards once the guitar riff kicks in and starts walking down the stairs in a continuous shot.
The next scene would be people dressed up in a exaggerated broken style costumes of normally jobs. Ex. A nurse with huge hair and thermometer earrings. The good Katy leads them to the queen in rebellion and then there's the whole Britney style orgy scene in the bridge.
Finally they take out the queen and theres a big dance scene, Katy then walks up to the thrown and sits down in the chair, and takes the cat. As Katy sings the final words of the song the sun rises, the scene becomes identical to the very beginning, meaning that they are destined to do this every night.
Oh yeah, and interpolating all those scenes shell be dancing in front of a wall with lights moving behind it in a tight silver body suit, with straight long purple-y black hair down to her chest.
Let's hear your video concepts !
and to think this song is almost two years old 
