New York has Pac-Mahattan, Singapore has Human Pacman.

The Mixed Reality Lab is also setting Pacman loose on the streets with an augmented reality game.
This one is using wifi, Bluetooth and GPS, head-mounted displays and inertia sensors (to sense a body's position and head orientation); the system allows players to turn into the yellow cookie-muncher or one of the ghosts. Pacman's efforts to find cookies and avoid his enemies can also be influenced by online helpers who can see a visualization of the game on a computer screen and send messages to the player, or to his pursuers.

"We're looking at next generation soldier platforms where they'll have kind of a smart suit," said Dr. Adrian Cheok of the Mixed Reality Lab. "As the soldier moves out into the battlefield he'll get live information directly into his viewpoint using these specialized head-mounted displays." The team is now working on a mobile-phone based commercially-available version of Human Pacman.
"We're aiming to take Human Pacman to more mobile devices," he explains. "Within two years we'll be able to see full commercial Pacman-type games on the mobile phones." (Via Blueserker.)
The interaction between online and offline players reminded me of "Can you see me now?", a game by Blast Theory that I tested last month. In Summer- Fall, 2005, Blast Theory will install an interactive multi-player game in Lower Manhattan. We'll keep you posted as soon as we get more details so you'll have no excuse to miss it if you're around. It's a fantastic experience, though I admit that you sort of look silly running in the street trying to catch an invisible opponent.