MICHAEL Lang and Joel Rosenman were two of the producers of the original Woodstock festival 40 summers ago. Lately, they have been trying to pull together an anniversary concert this year, they really have, but you have to understand, man, it’s complex.

Part of the problem is that they have a few disagreements.

“The first conversation we had about Woodstock for this year was probably nine years ago,” Mr. Rosenman said last week.

“We started thinking about it about a year ago,” Mr. Lang said in a separate interview.

While the partners’ most promising idea  a one-day mini-Woodstock in Prospect Park in Brooklyn this August  fizzled when they could not find sponsors, that doesn’t mean others haven’t coaxed a few more marketing miles from the creaky Woodstock bus.

Dozens of projects are planned to commemorate the August 1969 concert, including an Ang Lee movie called “Taking Woodstock,” a Heroes of Woodstock concert tour (with Jefferson Starship and Melanie) and at least 13 books, including one for children co-authored by a second cousin of Max Yasgur, the farmer who lent his land in Bethel, N.Y., for the original event. Target is set to run a “Summer of Love” promotion featuring licensed Woodstock merchandise, like beach towels with the symbolic white dove perched on a guitar neck.