Seth Hurwitz, co-owner of the District's Nightclub 9:30, picked up the phone late last year and called a Rouse Co. executive to make what he described as a far-fetched pitch.

Hurwitz asked Rouse, which owns Merriweather Post Pavilion in Columbia, to oust the pavilion's operator and hire his tiny Bethesda company, I.M.P. Inc. Though I.M.P. booked shows for Merriweather in the past, Hurwitz figured his bid to replace radio broadcasting goliath Clear Channel Communications Inc. was a long shot.

It came as no surprise to him when the Rouse executive declined the offer, saying he planned to renew Clear Channel's contract.

"Then, inexplicably, the next day [the executive] called back and said he was interested in talking to me, and we got the deal," said Hurwitz, 46. "It was like a fantasy. It was like being in the amusement park business and getting the chance to take over Disney World."

But nine months into its deal at Merriweather, I.M.P. is enmeshed in a showdown between Rouse and some community activists in Columbia over the future of the landmark pavilion, built in 1967 to serve as the city's cultural hub.

About two years ago, Rouse began applying for permits to develop 51 acres surrounding the nine-acre Merriweather site, including the pavilion's parking lot. It also announced plans to enclose the 19,000-seat, open-air pavilion and convert it into a much smaller year-round performing arts venue.

In defending its decision, Rouse cast the pavilion as an outdated, money-losing operation that has been in decline since the 1990s, especially since 1995, when the larger Nissan Pavilion opened in Virginia. Rouse points to the numbers: Merriweather hosted 19 shows in 2003 before I.M.P. took over, compared with more than 50 shows a year in its heyday.

In June, Rouse offered to sell Merriweather to Howard County for an undisclosed sum if the county agreed to enclose it. Community activists revolted. Some organized a "Save Merriweather" campaign. Other residents groused about Rouse's plans for the adjacent site. And a few balked at using public money to buy Merriweather. Rouse gave the county exclusive purchasing rights until the end of the year, an option Howard County is studying.

Adding to the anxiety: General Growth Properties, which agreed in August to purchase Rouse for $7.2 billion, has not weighed in publicly on Merriweather's fate. Most likely the Chicago-based shopping mall developer will not do so until the deal closes as expected later this year.

Until then, Rouse must decide whether to renew I.M.P.'s contract, which expires Oct. 15.

"We brought Seth in because he had experience promoting enclosed venues" such as Constitution Hall and the Warner Theatre, said Dennis W. Miller, Rouse's vice president and general manager of Columbia. "I told him when he signed the lease that the plan was to turn it into an enclosed venue, and we consistently informed him of that."

Hurwitz agrees that Rouse told him that early on. But he disagrees with the strategy and the reasoning behind it.

"I went into it with the understanding and promise that we would adapt to whatever the future use would become," Hurwitz said. "But it's pretty clear that a smaller, enclosed venue would not last a year. It would go out of business."

Hurwitz launched I.M.P. (short for It's My Party) in 1980, at age 22, from his bedroom at his parents' Potomac home. Fellow music buff Rich Heinecke bankrolled the deal. The two met when Heinecke (who is 10 years older than Hurwitz) was a substitute teacher in Hurwitz's electronics class at Winston Churchill High School in Potomac.

After graduating, Hurwitz held sales jobs at record stores before managing the now-defunct Ontario, a funky beat-up theater on Columbia Road known for showing action movies. At the Ontario, Hurwitz presented his first concert, featuring the Ramones and paired with a showing of the newly released movie "Rock 'n' Roll High School."

Within months, I.M.P. decided to begin booking only concerts and it shopped its services to the 9:30 club, then located at 930 F St. NW. Six years later, I.M.P. purchased the club and, in 1996, moved it to a larger site on the corner of Ninth and V streets NW.

As the club's popularity grew, so did Hurwitz's reputation as an independent concert promoter. I.M.P. began booking shows at larger concert halls and butted heads with groups such as Cellar Door Productions Inc., which owned the Bayou, and Clear Channel Entertainment, the concert division of Clear Channel Communications.

In 1998, the Nederlander Organization, which had the contract to manage Merriweather, hired I.M.P. to book shows there. In 1999, SFX Entertainment Inc. took over the management of Merriweather and continued to use I.M.P. to book performances. In 2000, Clear Channel Entertainment acquired SFX and honored I.M.P.'s contract until it expired in 2002.

In 2003, Clear Channel, which also owns the Nissan Pavilion, took over Merriweather's operations. Soon, some Merriweather supporters said Clear Channel was steering the best shows to Nissan, a claim that Clear Channel has denied repeatedly. Clear Channel said performers usually prefer the Nissan because its larger size allows more tickets to be sold, and bands get a cut of the ticket sales.

I.M.P. took over management of Merriweather in January. Hurwitz said it sunk hundreds of thousands of dollars into refurbishing the pavilion and has scheduled 26 shows this year, including name acts such as the Dave Matthews Band.

Hurwitz said the pavilion will turn a profit. The only shows that haven't been profitable are the ones geared to older audiences, the demographic Rouse hopes to attract to a smaller venue, he said. For instance, Hurwitz said I.M.P. lost a "ridiculous amount of money" on jazz singer Harry Connick Jr.'s show in June, which drew 3,193 fans. But it made money on pop-punk band Dashboard Confessional, which drew 4,500 people the same month.

"It's all relative to what we're paying the band," Hurwitz said. He declined to disclose dollar amounts.

Merriweather supporters argue that it should be irrelevant to Rouse if Merriweather is profitable as long as I.M.P. pays the rent. But Miller disagrees, saying Rouse's finances are affected by Merriweather's profitability. "That has to do with clauses in my contract with I.M.P. that I am not willing to discuss," Miller said. "That's information between a tenant and landlord."

Miller said that although I.M.P. has done a much better job than its predecessor, the venue remains underused and faces tremendous pressure from Nissan Pavilion and Wolf Trap. "To extend the life of the asset, an enclosed theater could be used 52 weeks out of the year," he said.

Howard County Council member Ken Ulman (D-West Columbia) and several others opposed to Rouse's proposals say the company is pushing to shrink and enclose Merriweather because of its plans to develop the pavilion's 42-acre parking lot.

Miller denied that. He said the effort to enclose Merriweather is simply one to extend its use. He also said the land around the pavilion has been slated for construction since 1967. Rouse was only waiting to develop a critical population mass before proceeding, he said

Almost two years ago, Rouse proposed building residential units on the site, which the county rejected. Rouse is appealing that decision in court. Rouse's proposal to put offices and big-box retailers on the site is under review by zoning officials.

G. Wilson Rogers, senior vice president and general manager of Clear Channel Entertainment, said it's obvious to him why Rouse would prefer to develop the land. "It's a no-brainer when you consider how much revenue they get from Merriweather versus how much revenue they could be getting," Rogers said. "We knew the future of this parking lot in this prime location was suspect."

Hurwitz is waiting for Rouse's decision and hopes that Merriweather can continue as an open-air pavilion.

"Luckily though, I don't have to fight that battle," Hurwitz said. "Others are fighting it for me."

Bethesda's I.M.P. Inc. drew a crowd to Merriweather Post Pavilion when it presented singer Norah Jones in August.