Poet James Russell Lowell once asked "What is so rare as a day in June?" The answer to that question for the Chicago area sports fans these days is a crosstown clash between the Cubs and White Sox when both teams are in first place.

This is almost like the stuff of paradise - or the Apocalypse, depending on your point of view. The teams play three games at the Cubs' Wrigley Field this weekend and follow that up with three games next weekend at the Sox's U.S. Cellular Field. Emotions are running almost as high as the price of the tickets.

John Wilson, owner of Box Seat Tickets in Valparaiso, said demand for tickets for both team has been high since May, but it has gotten crazy in the past week or so. The cheapest ticket at Wrigley is about $220 while "Cell" seats start around $160, Wilson said. To avoid the nosebleed section, fans could find their wallets $800 lighter, especially at Wrigley.

"There are more Cubs fans than Sox fans, so the demand at Wrigley is huge," he said. "I've got 1,000 tickets for every game, from the cheapest to the most expensive. The prices are putting a lot of people out of the market, but people are so hyped, especially Cubs' fans, because they think they have a good chance to go to the Series."

Wilson said he's getting calls for tickets from people who haven't gone to a game for 20 years. Sporting goods stores are benefiting from the bonanza as fans are indulging in a bit of a buying frenzy to demonstrate their support. Which team is more popular, based on the number of items sold? Depends on which store you talk to.

Mike Gadzala, general manager of the Sports Authority in Hobart, said, "The Sox racks are a little bit lighter, so I assume they are selling more than the Cubs. It's a little more intense this year with both teams in first place. Fans are coming out of the woodwork."

Jeff Chapman, manager of the Dick's sporting goods store at the Westfield Shopping Center at Southlake, said the merchandise battle is going to the Cubs by a 3 to 1 margin. Chapman said he's having trouble keeping team gear in stock now and said the most popular item is the Kosuke Fukudome jerseys.

"The Sox have been consistently strong all season," Chapman said. "The Cubs have been strong, but they really exploded in the last week."

John Parsons, spokesman for the Northern Indiana Commuter Transportation District, said South Shore trains already have been beefed up because of the growth of weekend ridership, but two more cars will be added to two of the morning trains this weekend for those wanting to save the gas and leave the driving to someone else.

Next weekend, when the series shifts to Cellular Field, coincides with the start of the annual Taste of Chicago, for which the commuter district already plans to add an extra train each day during the three-day weekend. The schedule will be available on the district's Web site, www.nictd.com.

A spokesman for the Chicago Police Department said the city will be taking "all necessary precautions, as we would with any major, large-scale event. We do not anticipate any problems and are prepared to respond accordingly."

Responding accordingly is exactly what Cubs and Sox fans plan to do for the next two weekends. After all, something of such historic significance might not happen again for a long time.