A futuristic system, Sensabubble, could alert you for Twitter notifications with little scented bubbles.
According to CNET, Sensabubble is a system that allows colors, text, and icons to be projected on bubbles that are filled with scented fog.
Sriram Subramanian, professor of human-computer Interaction in the University of Bristol Interaction and Graphics group has made a prototype of Sensabubble, for Twitter notifications, but the model is not portable.
Subramanian explains possible usage of the device in museums, advertising, alarm clocks or education.