So first thing's first, taxes are due on the 18th this year, not the 15th. For the trivia minded, the reason is Emancipation day, the anniversary of the signing of the Compensated Emancipation Act by President Lincoln in 1862, which freed the slaves specifically in Washington D.C. This is usually on the 16th, but since that's a weekend, D.C. is recognizing it a day early [source: fivecentnickel.com]. It may only be offically recognized as a public holiday in one place in the country, but when that place is the same one responsible for taxes, it results in the due date getting pushed forward a bit.

On a more serious note, even with those extra few days, some members or clubs might need a bit of an extension. In that case, the IRS has provided a few forms you can use to request such a thing at:

http://www.irs.gov/formspubs/article/0,,id=98155,00.html

Individuals will want to look at Form 4868, Clubs will want Form 7004