Lots of sponsor participation at the recent Fortune Brainstorm conference in Colorado, but AT&T should get additional kudos for really adding value and staying consistent with their brand (phones!). They supplied a phone charging lockbox (pictured at right). You could put your phone in, hook it up to Apple, Android or Blackberry chargers and lock it up. In some public places these sorts of stations would be maintenance and liability problems, but would love to see similar terminals in more locations.
Have you come across similar sponsor provided pop-ups that are useful and on-brand (ie not a credit card company sponsoring a massage station)?