If you've ever wanted to enter one of those "guess how many" contests, Old Dominion Freight Line Inc. is providing the opportunity.

The Thomasville, N.C.-based less-than-truckload (LTL) carrier will award a pair of tickets to one game of each of the next three World Series to the contestant who comes closest to guessing the number of baseballs it takes to fill its custom promotional baseball trailer. The trailer, which was designed and built by Lafayette, Ind.-based trailer manufacturer Wabash National Corp., features a see-through design that gives people a clear look at the unusual cargo.

Old Dominion introduced the trailer in Miami during All-Star Week in July. From there, it embarked on a cross-country tour to visit the seven teams that Old Dominion sponsors: the New York Mets, Boston Red Sox, Chicago Cubs, Chicago White Sox, Texas Rangers, Los Angeles Angels, and Kansas City Royals.

Fans can enter the sweepstakes online at odfl.com/tickets. The deadline for entries is Aug. 31.

For the record, David G. Ross, who covers Old Dominion for the investment firm Stifel, guessed that the trailer holds 125,000 baseballs.