I did one a few years back in Texas, an (not so)organized ride to see if we could put a team together to raise more $$ for the MS ride. Nothing came of it cept that me n a few buds rode fixed and kept up just fine. None of us ended up doing the MS150 that year though
all flats, no hills at all cept one bridge. Flat as...anything flat, great rides for fixed if you can get out of the city