I'm using a MacBook Air (latest OS X update) and today the number & punctuation keys on the integrated keyboard stopped working. All other keys are working correctly.
And no: there was no water damage. I didn't install any tools today.
For a few weeks I've been using a MagicKeyboard over Bluetooth. Today I connected, disconnected and powered off the keyboard after disabling Bluetooth. I never had this issue before.
For me it seems like there is a "numeric disable" activated, similar to the "num"-Key on keyboards with a numeric block. But this makes no sense...