What are all the endings of Façade and how do I find them?
Endings I've found so far:
Get kicked out: say enough offensive things or make enough unwanted advances. (Talking about Grace's melons is an easy way to trigger this outcome.)
Get Grace to leave: ask Grace a lot of "why" questions and whether she's happy/loves Trip, etc. When Grace asks whether everything you've been asking has been toward some particular purpose, say no, and she'll choose this course of action; saying yes will cause her to admit to sleeping with a fellow artist, but she'll still leave.
Get Trip to admit to the affair with Maria and then leave: direct your questions primarily toward Trip along the same lines as number 2 above; when he asks if everything is adding up to something, say yes.
Get Trip to admit to the affair AND get Grace to admit to sleeping with Vince, and they wind up staying together: just like in question 3, except answer "no" to Trip's question.
Have Trip admit to being ashamed of his parents in comparison to Grace's parents. This will make him break up with Grace and leave. This consists of siding with Trip mainly until him and Grace start asking you yes or no questions.
I got Trip to admit that he purposefully asked her to marry him in front of a public to force her into it, and also that he just can't accept the idea of having an artist wife, hence pushing her into advertising instead. They calmed down and said they'd need to talk it over, and wished me a good night.
As for what I did to get this ending, I picked up the 8-ball and quoted it through almost all of the scene («Ball says "Maybe"»), said random but unoffensive crap, pointed at everything, and told Trip, who asked me if I was leading up to something: "Nah it was just random crap." :P
Still, it was a very satisfying ending for the very low amount of meaningful input I've given this thing :P