On a breezy Wednesday morning, Costas Schuler pulls up to Aroma's Coffee in downtown Santa Rosa. Within minutes, a handful of people have already surrounded his car, touching it, peering inside, asking questions, and laughing.

Schuler's 1981 Mercedes Benz is covered with more than 10,000 pens, including ball points, dry erase markers, highlighters, and a host of other discarded writing instruments. On top, trimmed drain pipes hold color-coded Crayola markers, while inside, gel pens bent by a heat gun make curvy formations on the brightly painted doors. Wooden pens clutter the dashboard, secured with Velcro so they're easy to grab. Even the ceiling has pens.

"This is the kind of car you want to see when you're in a bad mood, or when you're sitting in traffic. It's definitely not one you'd want to smash into," said observer Micheline Cavallacci, a 50-year-old physician's assistant.

But Cavallacci is most surprised by Schuler: "I would have expected some old dude with a long ponytail to step out." Instead, Schuler, 40, is clean-cut, sporting a navy pullover, cargo shorts, and hiking sandals. His 14-year-old daughter Emma sits shyly in the passenger seat sketching anime drawings. She's the oldest of Schuler's four children, and one of three that Schuler and his wife homeschool from their Forestville home.

Inspiration for the car, called "Mercedes Pens," came in 2003 when Schuler, a graphic designer, read a book on art cars by Berkeley author Harrod Blank: "I've been in the arts for a long time, but this struck me as such a joyful expression of creativity. I had no idea what to do with it though -- once you start painting or growing things on your car, you're committed."

Two years later, Schuler woke up one morning with an idea of a pen car, something he hadn't seen anywhere else. He started by silicone-gluing 20 dried-up pens onto the Mercedes his friend gave him when his car broke down. Soon, he began collecting pens from local schools, doctor's offices, churches, and friends, while also starting a blog. As the car transformed, what started as a creative outlet for Schuler has turned into something he couldn't have anticipated.

"I didn't start out thinking it would be this big statement...it's become an amazing way to reach people. I've had incredible favor with this car," said Schuler, who was born in Greece and spent part of his childhood in the Middle East before his parents moved to the Bay area when he was 13.

Now, Schuler has grown accustomed to local crowds gathering around the car, his only mode of transportation, and asking him questions wherever he goes. "My wife makes me take her car to run quick errands," he said.

But that's not all: After years of participating in the Bay area's Maker Faire and Blank's San Francisco Art Car Fest, Schuler is building friendships with people in the art car scene that he wouldn't have ever met otherwise. Media outlets such as the Smithsonian TV, Forbes, Huffington Post, Fox News and the UK's Daily Mail have featured stories about Schuler's car. He's been able to get more web design work from the publicity and enough Google ads on his blog to garner a modest monthly check. He's currently raising funds to create large murals out of the 60,000 pens he's collected so far from as far away as Africa and Thailand.

While the art car movement is often characterized by left-leaning political and environmental messages, Schuler said his car resembles something different: "As a Christian, I believe God is the ultimate Creator, and since we are made in his image, we get the privilege of creating. I think the car is an expression of how God touches people with his humor, his joy, and all that the car invokes in people."

Outside the coffee shop, Cavallacci realizes she's hung around Schuler's car longer than she intended.

"I don't want to leave. I'll probably be stuck laughing all day," she says. "I guess that says something about the car."