You can’t just ignore them. They are everywhere.
What kind of expressions/poses do you do when you’re riding by someone taking a picture or a car with four hands and four camera phones sticking out of the window?
I’ve recently been trying my best to think quickly enough to do the \m/ XP \m/, but I think someone caught me doing that on videotape, and I didn’t make the “MMMMLEGH” sound to go with it. I’m not sure if I should or shouldn’t.
My general one is “try not to look stupid”. 
Generally, I ride like it’s my sport, not their cabaret, but I will raise a hand in acknowledgement, and smile and/or nod to the camera.
it depends on what type of riding i’m doing. if i’m out doing some XC or semi tech muni, i might look up at the camera and smile if i see someone taking pictures. however i’f i’m riding street or trials i assume that they want a pic of what i’m doing, not of me so i pretend that aren’t even there.
When I was in Saint Paul there was a group of about 40 Nepali tourists, and maybe 10 of them had cameras/videocameras aimed at me. I just did some basic tricks for them to ooh and aah about. But besides that I don’t have a whole lot of experiences with paparazzi, except for the occasional picture of me unicycling to/from school that someone at my school takes on their phone and puts on facebook.
Let me know how that works out for you!
Flash them.
This is why it’s best practice to always unicycle in a trench coat.
+1
If too many people gather, take off your cloths. It seems to make them feel awkward and they soon leave.
I ride with my shirt off all the time and people give me funny looks.
Indecent exposure!
The results are inconsistent. 
Generally I will either show off or continue going about my business, depending on the subject matter and my mood. If I’m cruising on the Coker, usually that’s what the person wants to see so I keep cruising.
When I did my RTL qualifying ride up Mt. Diablo last year, it’s the most I’ve probably ever been photographed outside of a show, parade or competition. Tons of people drove by slowly with cameras out the window, or stopped for better shots. For those I mostly tried to just keep on going, which is tough enough on most of that ride.
In a parade, I’ll do all sorts of things, from making a pose, to doing silliness for the camera. That’s my MO in a parade. And sometimes I’ll pull out my own camera and take a picture of them! Audiences always seem to think its ridiculous to attempt to take photos from a unicycle. I’ve been doing it for many years!
When someone takes my picture as they drive by in a car, I wave and smile and keep riding.
I don’t try to show off. If I did, that’s when I would fall off and look stupid. :o