Starting at midnight tonight, it's something like a birthday and Election Day combined for some 150 local nonprofit arts and cultural organizations.

Or so I'd assume, based on the deluge of Pittsburgh is Art Day appeals from such groups that have been flooding City Paper's inbox for the past couple weeks.

The deal is that for the 24 hours that comprise Wed., May 11, the Pittsburgh Foundation's PittsburghGives initiative is making a pool of matching funds available against any money that you donate to any of those performance groups, galleries, libraries, film festivals, museums and more.

As with other PittsburghGives days for other types of nonprofit enterprises, Pittsburgh is Art Day works like this. You, the individual donor, go to www.pittsburghgives.org and select a beneficiary or beneficiaries. The minimum donation is $15, the maximum $10,000 per group.

For every dollar you give, the Pittsburgh Foundation provides matching funds pro-rated according to the total amount of donations. So, according to the site, if "$1 million is raised against a $475,000 pool [of matching funds], the match will be .47 on the dollar. This is not a $1-to-$1 match. The exact match percentage will be released when the event is closed and reconciled."

While there's a credit-card processing fee of 2.9 percent, none of the funds goes to the Pittsburgh Foundation. Everything else, including the matching funds, goes straight to the organization.

The obvious upside is that your donation to your favorite theater troupe or arts-education organization goes much further than it would any other day of the year.

But another function of PittsburghGives, says the Pittsburgh Foundation, is that it helps to "[s]potlight the charitable trends in our region. Where are people giving? What are your community's nonprofits saying is vital and needed right now?"

In other words, May 11 is a great day to tell one of the region's biggest funders what arts groups matter to you.