Cyclists seeking donations for the Pan-Massachusetts Challenge -- a bike-a-thon that raises money for cancer research -- are getting a boost from a rich media campaign promoting the race's goals.

A 20-second spot, created pro bono by Santa Monica interactive shop Whitespeed and delivered in Flash, is being sent via email to 10,000 cyclists and past contributors to the race, which is being held Aug. 3-4 along six different routes in Massachusetts. The ad opens with piano music and footage of past races interspersed with text on the screen. Lines read, "3600 Riders from 32 States across the nation....Facing almost 200 miles....For a vision of a world without cancer."

The campaign also provides a link for viewers to contribute to the PMC's goal of raising $15 million this year. "It's an easy way for all of these riders to pass on the message," said Susan White, president of the four-person shop.

Last weekend, the ad, which launched July 11, has generated about $62,000 in donations. "We're hoping for the viral aspect to feed on itself," said Billy

Starr, executive director of Needham, Mass.-based PMC, adding that so far, 500 recipients have passed the message on to friends, and about 100 of those recipients passed them along further.