Whenever I feel the need to renew my faith in American ingenuity, there's no better tonic than listening to a bunch of college students present business plans.

The energy, the enthusiasm, the ideas. All were on display in Huntsman Hall on the University of Pennsylvania campus Wednesday when eight teams faced off in the finals of the 12th Wharton Business Plan Competition.

In recent years, student competitions have trended toward all things Internet. But six of the eight finalists at Wharton were medical start-ups, including the winner of the $20,000 grand prize, Cortical Concepts.

This team is applying the lessons of weekend home repair to spine surgery in an effort to reduce risks faced by patients with osteoporosis.

Just as you use a plastic or metal anchor that expands when a screw is driven into drywall, the students' Cortical Anchor would expand into bone, helping prevent pedicle screws from pulling out and reducing the need for corrective surgery.

The simplicity of the idea and potential sales of 720,000 units per year at $400 per unit swayed the five judges, who included Josh Kopelman, managing partner of First Round Capital, and Maxine Gowen, CEO of Trevena Inc.

For sheer entertainment, it was hard to beat the presentation of Kembrel.com, a private sales club. Like the Gilt Groupe or Rue La La discount "flash-sale" sites, Kembrel hopes to connect popular fashion brands with cash-poor college students.

When team member Aymeric de Hemptinne asked if any brand managers were present, up popped someone who said she'd worked for Guess Jeans. The audience was smitten and voted to give Kembrel the People's Choice award, worth $3,000.

Also intriguing was Hector Beverages L.L.C., which aims to sell healthy, packaged beverages in fast-growing India. Sold in a pouch rather than a bottle, its PowerWater would be priced at 8 rupees, or about 18 cents. In contrast, VitaminWater sells for 45 rupees, said Hector principal James Nuttall, a former packaging industry executive.

It's easy to dismiss these competitions as merely a stage to act out youthful dreams. But Wharton's is different. It has produced seven grand-prize winners that are still in business, making it more like Broadway than community theater.