Incubator Y Combinator just held its latest Demo Day, where the current class of startups gave rapid-fire demonstrations to investors and journalists.

It’s tough to judge a company based on a short presentation, and that was especially true today, since YC incubated a record 36 startups in the current class. To squeeze everyone in, the presentations were limited to 2 minutes 30 seconds. But I’ve selected five companies that deserve a closer look.

These aren’t necessarily the companies I think will be the most successful, or are the best investments. I chose them based on some combination of cool ideas and a desire to use the products myself. There were plenty more that I liked, but if I didn’t cut the list off somewhere I’d end up mentioning almost everyone who presented today. Oh, and many of the companies were in stealth mode, so I’m can’t write about them yet.

Enough disclaimers. Here are my favorites, in alphabetical order:

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brushes ipadBrushes — This startup created the Brushes application for painting on your iPhone or iPad. The app was used to create the well-known iPhone covers for the New Yorker. With 250,000 paying users and $60,000 in monthly revenue, Brushes apparently holds the YC record for most profitable startup on Demo Day. Its eventual goal is to become the “Adobe of touch devices” by building a suite of apps.

FutureAdvisor — This Web application clearly owes some inspiration to personal finance management site Mint.com. FutureAdvisor’s founders are pitching the site as an alternative to an expensive financial advisor. Users connect their brokerage accounts to the site, which then offers suggestions on reducing fees and projections showing how changes to their investment portfolio can affect retirement plans. The company says that since launching a few weeks ago, users have already connected accounts worth $170 million total.

Hipmunk — This startup from Adam Goldstein and Reddit cofounder Steve Huffman offers a great way to search for flights. It lays out your search results on a grid (making it easy to ignore redundant flights and spot the ones you want), hides flights that are worse in every way compared to other results, and more. I wrote about Hipmunk when it launched last week.

leftronicLeftronic — Leftronic builds software to display real-time data on large dashboards. For example, there’s a screen in the YC office showing statistics about the incubator’s Hacker News site. Cloud management startup Cloudkick uses Leftronic to monitor the status of its servers. The company’s founders say their goal is to support any kind of “ambient data,” where information is coming in constantly and you want to watch it in the corner of your eye.

Rapportive — This is far from the only startup trying to provide social data like LinkedIn profiles in email, but it already has the backing of Gmail creator Paul Buchheit. Chief executive and cofounder Rahul Vohra has told me his goal is to create the most easy-to-use and beautiful interface for this data.

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