Yes, its a giant “wide game” of zombie tag, which has apparently been run in various cities around the UK (Glasgow, Bristol, sound slike there have been others). Basically small teams get given a chain of locations, and have to get to them without being tagged by the zombies. With, of course, a party at the end.
Sounds like it could be fun, but its the sort of thing you’d really need to cooperate with the local authorities over, and make sure you have good media (so bystanders aren’t really alarmed by the gore-spattered zombie horde in their midst).