I propose a "luna" microformat, for marking up co-ordinates on our Moon. This would be based on the "Geo" microformat (and thus relatively easy to implement, since code for "geo" can be re-used).
Note, though, that  and  indicate that more than one system of recording the co-ordinates, for any given point, is in use, and it may be necessary to include an attribute to indicate which system is to be used, though the most recent standards appears to be the IAU Mean Earth Polar Axis co-ordinate system, as used by NASA and Wikipedia, and described in Davies and Colvin, J. Geophys. Res., v. 105, pp. 20,227 - 20,280, 2000.
Note multiple statements of Apollo landing co-ords here: 
- "Currently, the lunar geoid is being redefined with Clementine data, so the location (latitude, longitude, and elevation) of everything will change again very soon".
I believe the reference geoids for other planets are also under revision
Perhaps geo could be extended to encompass multiple grids. The existing type/value system in hCard 1.0 et al could be used. Available types would intially be 'Earth', 'Luna', 'Mars', with the default (if none is specified) being 'Earth'. These could be extended to add new grids when needed. The value is then the co-ordinate.
Obviously the name 'geo' applies to Earth, but we should seriously consider if we want to create a different microformat for every lump of rock someone wishes to map. It has to be advantageous to have a single format for this function that can be applied to any orbiting mass.