The Amazing Raise is a timed fundraiser for about a dozen Richmond nonprofits that include the Museum of the Confederacy and the Virginia Historical Society. It began this morning at 6 a.m. and will end at 6 p.m. Thursday.

Donors may make their contribution of $50 or more at specific times during the 36 hours to maximize their group’s chances of being awarded a grant of $2,500 or $1,000 in cash. For example, there is a $1,000 Primetime Prize on Wednesday for the organization that receives the most donations during television’s prime time programming, from 8 to 10 p.m.  On Thursday, the Rush Hour Prize is $1,000 for the group receiving the most donations between 7 and 9 a.m.

And when it is all over, the three top organizations with the most unique donors giving gifts of $50 or more will get a bonus of $20,000 for first place, $15,000 for second and $10,000 for third.

The Amazing Raise is sponsored by GiveRichmond, described on its Web site as a “powerful online tool designed to encourage charitable giving — benefiting donors, nonprofits and the community at large.”

Last year’s Amazing Raise received more than $630,000 in donations.