This spring I started going to local cemeteries. Not because I have any relatives buried there, but because other people do. I used my smart phone to photograph the gravestones for BillionGraves. It is very cool to be able to record the exact location via GPS for each headstone, and then transcribe them for a searchable index. The BillionGraves index is connected to FamilySearch database.
FindAGrave is a similar free service. But, instead of using your phone, you use a camera and upload the photos when you get to a computer. Their database is much larger. Of course, they have been around longer. This site is connected to Ancestry.
Both sites are totally worth it to join (especially considering they are both free). Sometimes one will have cemeteries that the other doesn't. And, both happily accept volunteers to photograph and transcribe graves. I personally have found several interesting family graves through these sites.
So, if you are looking for a fairly quick and easy project to do for Family History Month, check out these sites and volunteer to spend some time hanging out in a cemetery.