It hosts more than 150 events a year, everything from rock concerts and professional wrestling to basketball and hockey games, ice shows, the circus, and truck pulls. In short, Allstate Arena is a versatile entertainment center.

Getting things ready for each event also requires extreme versatility on the part of the people who operate the arena.

"Sometimes it can get tricky, but we always get it done," said Harry Pappas, executive director of Allstate Arena.

Pappas knows his trade: He began working at the arena the day it opened.

"My first job was setting up chairs, so I know what has to be done. It's pretty difficult for my staff to say 'no' to me because I've done it all," Pappas said.

Take the work to prepare the arena for a Saturday double-header featuring DePaul Blue Demons basketball in the afternoon and the Chicago Wolves hockey team in the evening.

On the main floor lies a thick sheet of ice that a basketball court must cover. The process begins with workers laying down inch-thick insulated board to keep the ice from melting. Then, the hardwood of the basketball court is applied, panel by panel, to prepare for the DePaul games. Carpeting and additional seating also is installed. The entire process takes a total of six hours to complete.

Once the basketball game is over, workers reverse the process for the Wolves hockey game. After the ice is exposed, Plexiglas panels and dasher boards are placed around the rink, along with nets and player benches. This process takes about two hours.

Pappas likes the basketball games to start no later than 2 p.m. so he can have the arena ready for a 7 p.m. Wolves game.

"We have to take into account that DePaul could go into overtime," Pappas said. "There have been times where we've gone down to the wire - people are walking to their seats while we've been putting the glass up for the Wolves game."

Creating the ice itself is a process that takes three days. At the base of the arena's concrete floor is a matrix of steel coils that resemble a giant ice cube tray. The coils are cooled to a temperature of 19 degrees, and a fine mist of water is applied to build up the thickness of the ice slowly.

When the ice is a half-inch thick, workers paint lines for the hockey game and the Wolves team logo. Then, more mist is applied to build the ice to a thickness of 1 inch.

When Disney on Ice show is scheduled, the surface is painted white and another misting takes place to add another half inch of ice in order to conceal the hockey rink. When the ice show is over, a Zamboni machine takes the surface back down to hockey game thickness.

When the Ringling Bros. and Barnum & Bailey Circus comes to town for a two-week run, it takes over the entire arena. The ice is melted, and Ringling Bros. transforms the building into a giant big top by setting up its lighting and sound system, the trapeze, and the center ring.

"The circus essentially makes this its headquarters. They take over office space, set up temporary dressing rooms, homes for the animals. It's quite an undertaking," Pappas said.

When there is a truck pull, the ice also must be melted, and 750 cubic yards of dirt - the equivalent of 100 truckloads - must be hauled in. A rodeo also requires dirt, but since the weight of the animals is less than the trucks, the ice is covered with the insulated sheets. When the shows are over, end loaders are brought in to remove the dirt.

"We can remove the dirt in one day after a rodeo and be ready. A truck pull shuts us down for a week because once we remove the dirt, it takes three days to build the ice back up," Pappas said.

Setting up for a rock concert also involves covering the ice with insulation and a temporary floor and then setting up a stage and 3,600 folding chairs.

To get the job done, Pappas directs a staff of 30 full-time workers, but that number can swell to 60 when there is need for a quick conversion. They mainly work overnight, making the arena ready for the next event by 8 a.m.

"There are times where we run a different event every day of the week," Pappas said. "We really run a 24-hour operation. There are very few arenas in the country that are as diverse and flexible as we are."