Please don't tell Lance Armstrong -- but is that Woody Harrelson making waves with Matthew McConaughey?
Well, they definitely weren't riding them, that's for sure.

The happy Texans spent a bromantic afternoon on the golden shores of Malibu, trying to get up on their boards (with trying very much the operative verb) while training for McConaughey's next flick, "Surfer Dude."

TMZ's resident Professor of Surf Science analyzed the footage, and gave Matty a grade of "Dude, he's a joke," and failed Woody outright. They did manage to throw a couple shakas at the cameras, and even emerged hand-in-hand after their ride, like two mermen in tandem.