This reminds me that when I was in Rome last April, I visited a couple of the churches that belong to the Vatican state. I talked to a couple of building guides, and they affirmed that I was indeed standing in foreign territory (away from Italy that is). Their badges had the flag and emblems of the Holy See, and they were employed by the Vatican City tourist office, not that of Rome. The guide at one of the churches (I can't remember which one off hand because I visited so many) suggested that a significant part of the territory in front of the church was also Vatican territory. I looked around in great detail, but the only sign of a border of any sort I saw was a row of short stone pillars along the inside edge of the sidewalk. If this was the border, it meant that there was probably (my guess) about 150 square meters of front yard space as well.
Brendan, do you have any information about these Vatican exclaves that might confirm or dispute what I was told?
Dallen