Maintainership is defined as a full release module where the user davereid is listed as the primary maintainer. The end of 2012 is defined as 1/1/2013 00:00 UTC.
You can see the number of project's where Dave Reid is the node author broken down by sandbox and regular.
At the time of this question's creation this number was 66 according to the project page listed above.
Dave Reid and his family (including cats or other non-human inhabitants of his household) are ineligible to participate in this bet.