First is that you need to see the movie, Into Great Silence, the award winning documentary which showed the life of Carthusians at Le Grand Chartreuse in France. I've shown it at adult ed programs, and it always intrigues people (plus, they love when I bring along bottles of green and yellow Chartreuse, you know, to show our support of the monks).
Next is this statue of St. Bruno:
In St. Peter's Basilica
I love this one. A few times, Pope Urban II tried to get his former teacher to accept appointment to the episcopacy. Bruno always refused, which is wonderfully depicted as Bruno repulses from the putto trying to get his attention to hand him a miter and crozier.
Finally, those who may want to know more about Carthusians can also check out their website.