The Giving Campaign is using the leap year as a hook for an appeal asking organisations to offer staff the chance to donate to charity through payroll giving.
The Big Leap campaign uses 29 February as a launch pad, but its creators want organisations to get involved throughout 2004.
Peter Gilheany, communications manager at the Giving Campaign, said: "The campaign is entirely speculative and is our response to firms telling us they have no reason to re-start their payroll-giving schemes. We're hoping the Big Leap will provide them with one."
A website, www.thebigleap.org, has been created to process registrations.
Branded with a leaping frog, the site will soon feature a game in which a frog leaps across the road to reach a payroll-giving scheme.
Once signed up, organisations will receive promotional materials such as posters, screen savers, newsletters and certificates.