From mine:
–parking permits for two community colleges
–a coconut-scented Cool Foot air freshener
–a lovely purple and gold woven pineapple with green plastic leaves and a tassel
My ID badge to get me into the building where I work.
Well, actually nothing right now; I’m at work, so I’m wearing the badge. But when I leave I’ll hang it there.
Parking pass (Zzzzz)
…bit of a personal question, don’t you think?
Nothing.
Of course, once I get a car, I’m sure there’ll be something.
[ul]
[li]Parking permit.[/li][li]SpongeBob SquarePants doll.[/li][/ul]
Nothing-- I drive a motorcycle.
Another parking pass, checking in.
But only when I’m parked on campus. Otherwise, there’s nothing there.
A monkey that I found in a roller coaster. And sometimes fuzzy dice.
The head of the last person who cut me off in traffic.
The testicles of my worst enemy. 'Course he wasn’t my worst enemy at the time…
Ugh. I hate crap dangling from rearview mirrors. When the cars are parked in the garage, the parking pass is put there. When we’re driving them, nothing.
A Rainbow Sash
I’ve got an Iron Maiden necklace hanging there. Been there for years. Most people freak out over it when they see it. 
Better not be a rosary, or you’ll get a ticket:
http://www.chicagotribune.com/news/printedition/chi-0212040348dec04.story
I love the smell of ignorance in the morning…
I don’t like anything hanging there, but last time my husband cleaned out my vehicle he found my air freshener and put it there.
It’s a Yankee Candle Company “Clean Cotton” air freshener. I feel like a soccer mom with that thing hanging there. I would take it down, but it does work better hanging in the mirror right there. haha
I’m such a nerd.
Partial hijack***
My Dad had an air freshener in the shape of a marijuana leaf nicely dangling from his rearview mirror…but did not know it was a marijuana leaf.
Quite funny when my sis and I piled in his minivan and said, “Dad, what the hell is that?!?! Do you know what that is?!??”
He did not believe us. He said he got it from the Dollar Store (Which he is addicted to). We laughed our a$$es off.
He now has it dangling from his cigarette lighter.
I have my graduation tassle from college (which is pathetic since I graduated in 97) and an Amish horse hex (good luck charm) a friend of mine made me for christmas last year.
A smiley face with a hard-hat on.
It’s an air freshener for my car that stinks of rotting cow beef…
I have a parking pass for the University of Maine and an individually wrapped cherry LifeSaver. It represents the main character in a short story I wrote about a man who poisons hitchhikers.