It's a popular dish in Singapore and Malaysia, and also finds its origin in Peranakan cuisine as far as I know.
It is a cocunut seafood curry with rice noodles, usually served with fish tofu, shrimps, egg and sometimes fish. It is usually served topped with cockles, laksa leaves and sambal.
While still quite unknown in many western countries (I think), Laksa paste (initial ingredient for making it at home) can be found more and more in Asian stores in the west.