Georgetown senior James Li’s team was among the youngest of the 25 start-ups competing to be “D.C.’s Hottest Start-up” on Thursday night in Arlington’s Artisphere.

Though they may have been too young to drink at the showcase and mixer — organized by tech media company Tech Cocktail — their business secured the most votes for the “hottest start-up” title on Tech Cocktail’s site.

Li co-founded Encore, a highly visual e-mail newsletter system allowing non-profits to share their staff’s stories with potential donors. The service launched officially on Wednesday. The start-up also provides non-profits with detailed analytics about donor behavior.

The runner-up was JetJoose, a social network for flight crews to exchange recommendations about hotels, restaurants, and experiences in various cities co-founded by Ronan Keane. Event crowdfunding platform Eventstir — co-founded by Andrew Mason, a recent graduate of George Washington University, came in third.

Encore received 5,000 points from American Airlines for taking the top spot. JetJoose and Eventstir received giftcards to shoe e-commerce site Zappos.

Here are some of the other ‘hot’ start-ups selected by the Tech Cocktail staff:

Columbus, Oh.-based music streaming site lets users stream, search and get to know artists in their local music scene.

Uplift, Inc., a D.C.-based non-profit, offers science, technology, engineering and math classes for students between four and 19 years old at their facility in Southeast Washington. One of their programs, called YouthAppLabs, teaches software development. Uplift founder Leshell Hatley said she got the idea when as a computer teacher in New Jersey, she found many of her students couldn’t learn the basics because they “didn’t even know the alphabet.”

Praescient Analytics provides analytic services to both government and commercial clients and is based in Alexandria, Va.

College students and recent graduates may find dorm decor at Dormify , an online only e-commerce brand based in D.C.

Speek developed a new platform facilitating conference calls — in the months since its public beta launch in July, Speek has more than 50,000 users, co-founder Danny Boice said. “We’re working on getting to a million,” he said.

Two of the chosen start-ups catered to parents — bookacoach connects athletes and their parents to qualified coaches for private lessons, and Connect2parents is a Web-based tool allowing teachers to securely text parents important information about their child’s education.

Gryphn also developed a mobile security app.

Bizelo helps businesses centrally manage their inventory, and Team Visibility lets sales teams easily share sales data with each other and team leaders.

Organizations can use to track what’s trending from their members’, donors’ and customers’ social media accounts to develop more engaging campaigns.

Blastroots ’ patent-pending platform helps individuals start grassroots campaigns, beginning with social-media blasts.

Local Energy Technology — a D.C. based company whose technology is mostly used overseas — lets utilities companies connect with customers through their cellphones. Customers can pay bills, and utilities companies can better identify utilities theft, co-founder Luke Shoenfelder said.

Easy WebContent ’s platform helps users create Web sites and presentations, and Markerly developed a widget for Web publishers allowing viewers to share selected text via e-mail, Twitter, Facebook, or Pinterest. PersonSpot released a social publishing platform for users to publish and manage content.

Students overwhelmed by hand-written notes, virtual documents, Powerpoint decks and pdf files can use EnoteBook ’s iPad app to view them all in the same format.

Vookup is a virtual event planning platform, and Kojami lets organizations market their events and collect analytics on the campaigns.

Woofound develops apps and sites helping users find event and venue recommendations based on their personalities.