The convention, which began Monday, has been particularly energized this year by the campaign of presumptive Democratic nominee Barack Obama, who would become the first African-American president if elected, The New York Times reported Thursday.

A button handed out at Obama's campaign kickoff in February 2007 sold for $150 on the first day of this year's meeting, the organizers said.

Participants said they hope the excitement generated by Obama's campaign will drive more young people toward collecting.

"I'd like to see people buying inexpensive $2 Obama buttons today, hopefully 10 years from now become interested in Teddy Roosevelt or FDR or JFK and maybe 20 years from now they'll be interested in

Washington and Lincoln," said Rex Stark of Gardner, Mass. "That would be a good thing."

Stark said he sold a John Adams snuff box for more than $5,000 during the convention, which was scheduled to close Thursday night.