Have her use the camera to "see" surroundings and help. Similar to City Lens
It would be really cool if Cortana could access your phone's camera to "see" you surroundings. From there she could give you information on places, give you suggestions to what's near, and maybe even make small chit-chat comments on what you show her. I'm thinking something similar to Nokia City Lens, but a little more personable, and Cortana could talk while she looks around. Go wild with this idea.