Jason Katzer, one of the buspreneurs on board the Startup Bus, writes ideas for his team's project on the window.

FIREBAUGH, Calif.--It's standing room only, 25 or so entrepreneurs jammed into the aisles brainstorming ideas, and maybe, just maybe, building the next multimillion dollar business.

This is the San Francisco Startup Bus, one of six coaches ferrying "buspreneurs" to Austin, Texas, for the South by Southwest interactive (SXSWi) festival. Across the country, 150 people from all over the world have packed up their laptops and iPhones and agreed to spend two days aboard a bus with (near) total strangers. The mission Build the best business you can before Austin city limits.

My job here is to document what happens aboard the bus--will the buspreneurs be successful Will they fight Will we see the creation of an app everyone will use

Just two hours into the trip, as we roll down Interstate 5 toward Los Angeles at 60 miles an hour, the ideas are already flowing. And there's coffee. A lot of coffee. Eight liters, to be precise.

But let's not get ahead of ourselves.

An early start You'd think that you'd want several dozen entrepreneurs who are about to spend two days hacking and coding and trying to build the next big thing--all with very little sleep--to start fresh. But that's not how the Startup Bus rolls. Instead, we all show up at 7 a.m. in San Francisco's tech center, the SoMa district, ready to get on one of two buses that will soon be heading for Austin.

With several dozen people milling around outside the offices of Vast.com, where Elias Bizannes, the founder of Startup Bus, works, the buses arrive. The door to the first one opens, and the driver quips, "Are you going to Texas"

There are two buses leaving from here--the San Francisco bus, and the Silicon Valley bus. That's odd, since both are departing from San Francisco. So for a few minutes, there's a bit of controlled chaos as everyone tries to figure out which coach to get on. All the while, buspreneurs--that's what those on board are being called--are loading supplies, grabbing free snuggies and hats, and doing a little get-to-know-you.

Our route is taking us straight down from San Francisco to Los Angeles--something that fails to thrill several buspreneurs who did the drive in reverse yesterday. Apparently, the original route for this trip would have taken us through Las Vegas, but the bus company ultimately said that wasn't on.

The buses feature a combination of six four-person tables, and a bunch of regular seats. Folks have quickly grabbed the tables, and some are already wondering whether having a seat at one of them is an advantage.

I look up as a guy on my bus comes through the door. He's smiling and says, "I just talked to the Silicon Valley bus and they're scared s---less of us."

Being on the West Coast, we're behind the buses that left from points further east. But that's a winning condition to Jonas Huckestein, who is running the San Francisco bus. "We're the last bus to leave its hometown," Huckestein said as we pulled out. "Which means we're going to win."

Huckestein then introduced himself, recalling that he was one of the buspreneurs on the single inaugural Startup Bus last year. "There's six this year, all being run by alumni," he said. "So this will be you next year."

But who are we Aside from our driver, a sponsor, Huckestein, myself, and another reporter, everyone else is a buspreneur. There's Albert ("I'm a hacker"), Rahim, Mischa ("I work in product at Twitter"), Jason ("I code, but I probably shouldn't admit that"), Dave ("I was head of tech for Friendster and the Howard Dean for President campaign"), Andy (whose T-shirt reads "I'm not angry, I'm from Philly"), Anna (an undergrad at USC), Katie from Atlanta, Sepi, and others. There's buspreneurs from New Zealand, Australia, England, and several U.S. states.

For some reason, though there are supposedly two dozen coders on this bus, few seem willing to say so in their introductions. So one guy says, "I'm a coder....I'm probably going to hide in the corner and hope no one finds me--unless they have an interesting idea."

Though this is a team competition, there's a lot of cooperative sentiment on display. Buspreneurs are walking around sharing their skill sets and offering their services--even to members of other teams. "If you think you have a billion-dollar business, I can probably evaluate the idea for you," said one business development specialist.

Pitches Introductions done, it's now time for pitches. The idea here is that the buspreneurs will stand at the head of the bus and share their ideas for potential businesses. Though dozens will be proposed, there will be only six teams. So, six ideas.

Huckestein starts things off, suggesting an idea for a tool to help people from different countries learn new, localized, words.

"You stole our idea," two people seated together shout simultaneously.

"OK, cool, I guess we have a team," Huckestein says.

The ideas flow. A subscription service for helping asthmatics find an inhaler in an emergency' a bidding system for travelers to define the journey they want to have' a system for real-time audience ratings of conference presentations' a tool to help tourists figure out what food and drink should actually cost' a "disloyalty" system designed to promote patronage of local businesses over national chains' Bouncr, a "bit.ly for e-mail addresses'" the idea Huckestein "stole" that will localize slang' a blind-dating site called crazyblindhookup.com, and many more.

Interestingly, several buspreneurs return to the front of the bus multiple times with new ideas. Some seem clearly developed on the fly--others are things they've obviously had in mind for some time.

As all this is going on, the San Francisco Bay Area quickly fades away and is replaced by the California Central Valley. Lush and green after months of rain, the Interstate 5 route is prettier than I can remember it. Everyone is focused on their discussions and their teams, and it's a surprise when we suddenly pull to a stop at a Chevron station in a tiny town in the middle of nowhere.

This is a 45-minute breakfast stop. Mingling. Bathroom break. Maybe a little coffee. To some, it's a welcome interlude. To others, it's a distraction.

"We had good momentum until the bus stopped," saysJay Stakelon, a member of the Bouncr team.

And then, it's time to go again. This being a bus full of people who were strangers just a couple of hours ago, it takes a bit of cat herding to make sure everyone's on board. Huckestein tries to get everyone to count off, but several attempts abort as this group of experienced entrepreneurs stumbles over counting.

"How many entrepreneurs does it take to count to 31," someone says.

Please stay tuned for the next two days for constant updates from the San Francisco Startup Bus.