A Donor-Advised Fund allows you to transfer an appreciated asset (e.g., a stock that has gone up significantly in price) directly to the fund, which is considered a charity. As such, you do not pay taxes on the appreciation, and if you've had the stock for over a year you get a tax deduction for the full current value.
Once it's in the fund, you can then decide which charity to give it to, and they send a check. You can also hold onto the money in the DAF and send it to your charity of choice later on.