If the recession has been as hard on Madison Avenue as on other sectors, a lot of marketing types are probably free to watch daytime TV. And if marketing’s your game, that’s time well-spent. You can surf the kiddy shows and learn from the true masters of your art: environmentalists.

Their latest coup? Elmo, the most popular character on PBS’ “Sesame Street,” has gone “green.” Literally.

The environmental left has accomplished what marketers dream of: hooking consumers from a young age and creating customers-for-life.

What’s more, they’ve done it on the cheap. As CMI has documented, Nickelodeon’s “Big Green Help” gives valuable web resources, ad time and talent resources to getting kids to “pledge” to take carbon-reducing actions and to annoy their parents into taking them too. Just last week, Nick used valuable airtime during its “Kid’s Choice Awards” to bestow the “Big Green Help Award” on actor Leonardo DiCaprio (who’s probably as relevant to today’s 10-year-olds as Clark Gable).

Having already conquered the preteen market, and emboldened by evidence that it’s made important inroads with adolescents, the Gaia Conglomerate has scored the ultimate product placement victory – for free! The traditionally red Elmo was literally “turned green,” in a new “Sesame Street” DVD called “Being Green” to teach preschoolers about all environmental pieties.

Sure, PBS and the Sesame Workshop are likely candidates for environmental marketing. If you want to sell beer and salty snacks, go to ESPN. If you want to sell environmental awareness, you go to the one-worldy network with an audience of future community organizers. But getting Elmo on board is no less genius for all that.

And just to make sure that it’s a smooth transition when the little ones graduate to Nickelodeon, the DVD gets them used to “pledging.” According to part of the DVD’s description, “Elmo, Cookie Monster, Rosita and Telly join Mr. Earth in pledging to continue to do ‘green’ things to help our planet because Earth Rocks!”

It’s never too early to politicize children, and it’s never too late to manipulate their indulgent and distracted parents. So Elmo has hit the road selling the DVD on NBC’s “Today” show April 2.

“Paul Rudd plays Mister Earth and he visits Elmo and the gang to teach them that the planet really rocks and is worth preserving,” explained “Today” co-host Meredith Vieira. “But in the process, Abby Cadabby accidentally turns Elmo green. The little guy’s upset of course, obviously, but eventually he learns the importance of recycling, conserving water and energy and respecting the planet.”

During the interview that followed, Elmo flirted with co-host Ann Curry and explained the crafts he’d brought that could be made with recycled materials found at home. “Being green,” it turns out, “is really cool” and “everybody should do it.”

“And I think when you learn as a very little kid, right, about all those things about the environment, that it sticks with you,” Vieira prompted Elmo.

“Yeah it does,” responded the Muppet. “So then when you become an adult you can do it too.”

That sounds like a primer in marketing principles. Or, in this case … indoctrination principles.