imagine a log of marinated lamb on a spit, slowly being roasted
with a charcoal fire...
it's cut off the spit into tender and juicy chunks..
added on pita with lettuce, tomato, onion, some herbs, a squeeze of
lemon, tzakziki sauce.. rolled up...
good stuff! 
p.s. if you cannot find The Souvlaki Bar, you can also go to
LAMBS.. about as good too 