I have some fish sauce and can't think of anything to use it in other than pad thai or a vietnamese salad dressing. Any other ideas?
Use it similar to soy sauce, or anything salty. It's anchovies, really, and when heated becomes a bit nutty.
My mother makes chicken soup and uses a spoonful or so of it. Never have seen her use it in a beef or pork dish, though.
I've stir fried veggies with just a seasoning of fish sauce.
It's also a nice salad dressing when heated with sugar and chile, although maybe you do this already.
I just finished "Ruhlman's Twenty". Fish sauce seems to be his secret ingredient for a lot of things... soups, sauces, marinades... anything that needs a hit of umami. I'm thinking I need to get some!
As joonjoon says, use it like salt. It can replace anchovies in certain dishes, but it's just as good adding a certain briny salinity to anything from rotisserie-chicken marinades to soup.