The Nokia 9000 and 9110 mobile phone / PDA devices. Looking like largish mobile phones, they reveal an entire little computer complete with QWERTY keyboard and a nice little screen when flipped open. They flip indeed open like a waffle iron. These beasties can fax, e-mail and manage addresses and appointments for you.
At IT shops (e.g. where I work at the moment) you can find Real Men walking around with Nokia Communicators on their belts. Don't believe they use it to fax dirty jokes to each other or manage any personal information. They use them as dumb terminals to log into VMS or Unix machines via infrared or such.