Jetpack Joyride is now playable on Facebook for free. Yes, adventure after adventure after adventure with Barry Steakfries is now just a few clicks (and a few onerous Facebook permissions) away.
It's worth noting that the game is currently in beta, and some of the seams are definitely showing. The visuals aren't terribly sharp and we even ran into some display issues, specifically if your browser view settings are zoomed in.
Again though, it's Jetpack Joyride, excitingly and horrifyingly more available than ever.