Ideas
Tie, with the use of strings, one brush to each one of a cardist's fingers. Hang these brushes so their tip almost touch the canvas. As the flourishes starts performing, the brushes move by themselves and paint a picture.
The following is a routine that has been practiced before. A writer sits in front of his typewriter and a cardist sits next to him. The writer starts well...writing haha how the cardist should move and he says this out loud as well so the spectators can hear. If you develop a routine with a friend this way, he can memorize the different movements to your cuts, so when he's writing what you should perform, he's actually writing and saying out loud a perfect description of the moves you can already perform.
Get a friend to film you underwater. No more said: cardistry underwater and you got yourself a viral video. If you really wanna make it viral, you get kendama users in there as well, tutters, spinners (hahaha), rappers, beat makers, skaters - all performing something underwater. Morgan Freeman type of voice should be doing a voice over, pointing out to how society is trying to drown us, how people around us are trying to discourage us, to bring us down, make everything seem harder than it is.