Y Combinator's stars shine at Demo Day

MOUNTAIN VIEW, Calif.--Twice a year, Sand Hill Road, the most important hub for venture capitalists in the world, empties out for a day. But it's not vacation that pulls away all the VCs -- it's Y Combinator Demo Day.

At the Computer History Museum here today, the heart of the tech investing universe came together once again to see, up close and personal, what the 74 companies in the summer class of Y Combinator have been working on all summer.

As is the case with any demo day, there were plenty of misses. But given Y Combinator's reputation as the world's most important tech incubator, its previous success at picking winners like Airbnb, Bump, Dropbox, Reddit, and others, and the $170,000 or so that participating companies get, there were also a number of companies that look like real hits.

Perhaps the most impressive of the on the record companies -- the last group to present, all of which were off the record -- include some very promising technologies -- was Double Robotics, which showed off a $2,000 telepresence robot (see video below) that it calls "Wheels for your iPad," and which it touts as something akin to the marriage between a Segway and Apple's tablet.

Designed for any number of potential markets -- from real estate to elder care to college recruiting, the Double robot wheels around using a sophisticated gyroscope and accelerometer combination to stay balanced, even if it's pushed, connecting its iPad to another one somewhere else for a video chatting session. It is very narrow, allowing it to fit in tight spaces, and is much cheaper than competing telepresence robots from companies like Anybots and Willow Garage, said CEO David Cann.

And while Double Robotics expects people to use the robot for things like adults checking in on their disabled parents, Cann said the more exciting potential uses may be what third-party developers come up with when the company releases a software development kit at some point in the future.

Already, Double Robotics has sold out its initial run of the robots, is involved in beta tests at companies like Coca-Cola and Johnson & Johnson, and has taken orders from seven Fortune 500 companies.

The best of the rest
The 74 companies that presented at Demo Day today showcased products ranging from gaming accessories to new social networks to ways to find cheap airplane flights and everything in between. Here's CNET's list of the best of the rest (in no particular order):

• BufferBox: This Canadian company has developed a new way for people to receive packages -- at their convenience, rather than that of the post office or FedEx. The system revolves around the installation of kiosks in central locations and e-mailed PINs that recipients get when their parcel arrives. Instead of the massive inefficiency of today's system -- where 60 percent of deliveries fail because no one is home -- the recipient can go to their local kiosk and retrieve their package from the specified locker.

• Airbrite: The value proposition of this startup is that very few e-commerce sites allow users to checkout on mobile devices, despite the fact that mobile users appear to be much more likely to buy something when they visit an e-commerce site than are those doing so on a computer. As a result, Airbrite has developed a mobile API that helps sites easily offer working checkout on iOS and Android tablets.

• Voicegem: This Y Combinator graduating company has built a system that is said to enable any two people, existing users of the service or not, to send each other voice messages via SMS. Voicegem doesn't require any sign-up, and any email address can be the recipient of a message. Users have included Stanford University, which the company said used the service this week to welcome its entire fall incoming class.

• GetGoing: Designed to make it possible for travelers to get airplane flights at up to 40 percent discounts, this startup has come up with a system for helping airlines sell excess inventory directly to targeted leisure travelers. The service asks users to identify some travel criteria (for example, only flying non-stops in the morning) and then pick two specific flights to final destinations (say, San Francisco to London and San Francisco to Amsterdam) they'd like to visit. The traveler sees prices for the flights, and then makes payment. At that point, GetGoing tells the user which trip they're going on, a booking that will be at up to a 40 percent discount.

• ReelSurfer: This service is based on the idea that many people don't have the patience to watch full-length Web videos but enjoy viewing shorter clips. As a result, the company has come up with a system for creating 15-second clips based on longer videos, yet does not host the content. Rather, the original source still hosts the videos, while ReelSurfer serves up the shorter versions.

And users can clip their own YouTube or Vimeo videos by pasting in a URL and choosing the 15 seconds they want to highlight. They can then share their creation with anyone.

• SpinPunch: This startup is banking on building a big business by enabling games to be played in any browser by using HTML5. The idea is that game developers could break free of the limitations of devices like iPhones and iPads that don't support Flash, and which require apps found in the Apple App Store to be vetted. Instead, any game could play through the device's browser.

To be sure, SpinPunch is not the only company working on HTML5 implementation of games. Another is GameClosure.

• Coco Controller: Another mobile gaming play, this is a physical controller that iPhone users can slip their smartphone inside of as if it were any case. But the Coco allows users to have a physical buttons to push when playing mobile games, which the startup argues is a big improvement over the touch-screen controls most people are used to on iPhones.

• Healthy Labs: Essentially a social-networking platform for medical patients, Healthy Labs has come up with a way for millions of people who suffer or have suffered from many different diseases to share information with each other. The founders argue that today there is no better way to do this than to turn to Web forums or Twitter, but with their service, patients will be able to communicate -- on networks that are specific to certain diseases -- and share vital things like medicines or therapies that helped them handle their maladies.

• Vayable: Designed to be the Airbnb of guided travel, this service allows anyone to create custom guided tours and offer them through the site. The idea is that travelers are tired of typical packaged tours and want something more personal. As a result, the service offers any number of different kinds of tours and the opportunity for people to create small businesses through the site.

Correction (11:10 p.m. PT): This story originally misstated the process that GetGoing's users navigate to select and purchase discounted airplane tickets.