Grand Rapids, Michigan
The Grand Rapids graticule is at latitude 42, longitude -85. It includes much of the Greater Grand Rapids area along with the cities of Kalamazoo and Battle Creek. Since the area is mostly farm land, the majority of meetup coordinates will likely be on private property, and meeting at the nearest public road intersection may be advisable.
Local Geohashers
Dawz: I'm actually from the Muskegon graticule, but more often than not it's far too wet for my tastes. My Saturdays are currently open.
Hakukoru: I'm from Grand Haven, so I may attempt to visit the coordinates for the Grand Rapids area as well, as long as they arent too far south-east. Especially with the current gas prices. Unfortunately I already have plans for this coming Saturday (May 24, 2008), but will check the coordinates for next Saturday and see how it goes.
smq: Live in SE Grand Rapids, work in Lansing. Don't know if I'll be able to make this Saturday (may 24, 2008) or not. Since no one has indicated they're from the K'zoo area, I'll probably try for North Creek Ct. in Rockford if I'm free.
24 May, 2008
The meetup coordiantes are in the far south of the graticule: a cul-de-sac at the end of a street in what appears to be a mostly-undeveloped subdivision outside of Vicksburg. The coordiantes for the next graticule north appear to be in a residential back yard in Rockford (oddly enough, also near the end of a dead-end street).