I heard about BillionGraves.com a while back, and now that my husband has an iPhone we thought we'd try it out, so we spent the late afternoon at a local cemetery photographing headstones, and I spent too long tonight transcribing and linking information to FamilySearch. This is so neat! I need to get some users on board in Japan, though gathering data from gravesites is not so simple there...
If you have some spare time and want to help others with their family history research, this is a fun and easy way to do it!