A look at the latest batch of winners--and promising ideas--from Harvard University's storied business plan competition.Harvard Business School hosts one of the most influential business plan contests in the country. Previous finalists have gone on to build great businesses, including some you’ve probably heard of: Rent the Runway, Birchbox, and CloudFlare, to name a few. Others’ ventures eventually IPO or get acquired for millions of dollars. Many of them create jobs and help transform industries. In short, the companies coming out of this competition are ones to watch.