Does it hurt your brain to look at the picture above? That'd be Chromium OS -- running on a MacBook Air! Pretty much the definition of "worlds colliding," this feat is brought to you by Hexxeh, whose most recent mind-warping project put Chrome on an iPad. The platform-mixing maestro says in this case everything works except Bluetooth, owing to a lack of support. But hearty souls who seek to follow in his footsteps, take heed: there's no dual-boot option, and you will lose OS X -- so perhaps this is a job for your now outdated model. Click the source link for 14 easy steps to turning your svelte laptop into Frankenstein's monster, but sadly, there's no mention of where to buy that hopelessly cute Chrome pillow.
Update: Diligent researchers found the Chrome pillow. Peep it in the second source link. Thanks, Matthew.