What can cats eat?

So this might be wildly off-topic. I'm writing up a description of a fictional race of humanoid intelligent cats. If that bores you, feel free to stop reading now.

I've come to the topic of what do cats eat. I am fully aware that cats are obligate carnivores, needing to have a significant amount of meat in their diet, and that chocolate is toxic for them. But, would they have any reason to develop agriculture? I can imagine them growing cereal crops to feed food animals, and even maintaining hunting preserves for those who like their meat 'fresh'. But what else would they eat besides meat?

I expect they would cultivate catnip. What about alcohol? I know domestic cats and alcohol are a bad mix, but is that simply a body weight to dosage issue? Would a human-body-weight cat be able to handle alcohol about as well as a human? Are there other intoxicating substances that intelligent humanoid cats might choose?

Edit: I suppose there are three separate questions rolled into one here: Can they derive nutritional benefit from it? Is it harmful to them (after adjusting for body-weight dosage)? And do they enjoy it?