Most years, Jim Nintzel uses part of his space in the Skinny to plug Arizona's Charitable Tax Credit program, but he ran out of room or forgot, so I'm stealing it.
How the credit works, as far as I understand as a person who sucks at money management, who probably shouldn't be allowed to give tax advice of any sort: If you give $200 as a single person (or $400 as a couple filing jointly) to a qualifying organization that works with either the poor or children with disabilities or who are chronically ill by the end of the year, you can get a dollar-for-dollar tax credit. This might not be the best budget move for the state of Arizona, but hey, the opportunity's out there.
If you go the the Arizona Department of Revenue's site (azdor.gov), you can see the complete list of eligible organizations, but here are a few local ones that seem noteworthy.
The Community Food Bank could always use the help, especially around this time of year. Through magic, I believe, they can turn every dollar donated into $9 worth of food. Plus, a donor has pledged to match every dollar donated before the end of the year. You can donate online or call them at 882-3296.
Mental health is obviously an issue still of concern to Southern Arizonans and organizations like COPE Community Services (792-3293) and CODAC Behavioral Health Services (327-4505) are out in the community providing services that are difficult to come by for those in need.
Parent Aid (798-3304) works to reduce child abuse in Tucson by offering parenting classes and dispatching Family Support Specialists to families who are having trouble dealing with the stresses of family life.
La Paloma Family Services (750-9667) works with at-risk children and knowing what we know about the state of CPS in Arizona, they certainly could use the help.
There are a bunch of eligible groups here (surely including one that fits your particular charitable affections), so if you've got some extra cash, consider doing a little extra good as this year comes to a close.