Katie Hill, a program associate with the Walker Art Center, shows a frame from a video of a cat playing the piano, in Minneapolis on Aug 29.?[Photo/Agencies]

Funny felines win netizens' love and earn money in the process.

They frolic in empty boxes and stick their heads under faucet streams of water. They dance on tippy-toes and fly through the air with Pop-Tarts. They play piano wearing little frocks and get tickled to distraction to the delight of millions on YouTube.

I speak, of course, of the cat stars of the Internet, a place filled with felines and their uploading humans since the dawn of bandwidth. Now, after years of viral viewing, they're coming into their own in lucrative and altruistic ways.

The first Internet Cat Video Film Festival drew a Woodstock-esque crowd of more than 10,000 people to a Minneapolis art museum in August. Police closed a section of highway clogged with cars trying to get to the Walker Art Center for the free outdoor slate of 80 videos culled from 10,000 submissions that covered simple, funny moments to polished animations and works made by trained filmmakers.

"People were spilling out into the streets. It kind of took our breath away," said the museum's Scott Stulen, who worked on the festival.

Corporate kittydom is happy with the higher profile for the cat, which goes back to the 1970s, when swapping VHS tapes was big and the word "meme" was barely known.

In addition to the Walker's free night in cat video heaven, Fresh Step litter sponsored Catdance, an evening of felines on screen that coincided with January's Sundance Film Festival in Park City, Utah. A fan-voted winner among five scripted finalists - 10 films were commissioned at the launch of the program - will earn $10,000 after online voting ends later this month.

Roly-poly Maru, the megastar in Japan with millions of views for nearly 300 videos since 2007, has three books and a calendar, among other swag for sale. The squishy-faced, often blissed-out Scottish Fold who loves boxes and bags, was used by Uniqlo when the Japanese brand launched its San Francisco store in October.

Not to be outdone, Simon's Cat, a funny feline in a series of line-drawn animated videos out of London, has a book and an online store.

So why cats?

Cats are fluffy and unpredictable and usually kept behind closed doors, which lends them allure and appeal that other common pets - I'm talking to you, dogs! - don't seem to have when it comes to vapid, funny or deranged video. At least that's what cat fans think.

"Cats are going to do what they want to do, and that's one of the reasons that we love them," said David Kargas, a Fresh Step spokesman who worked on Catdance.

These days in the cat video game, acts of charity are expected as much as laughs, said William Braden, the Seattle filmmaker who morphed a pampered family cat named Henry into the French-speaking Henri for a 2006 film school project. Cranking out Henri videos and managing the black-and-white long hair's growing projects are now Braden's full-time job.

"On the one hand, you'd be stupid not to do charity because fans are sensitive," Braden said. "On the other hand, for the love of God, I make a living doing this. ... How horrible would I be if I didn't give a little bit of it away?"