We started our house system this year, and, from what I can tell, it seems to be going very well. We wanted to create something to improve our school's culture and to give the students something to rally around. We named our houses after the four major epic poets: Homer, Virgil, Dante, and Milton.
We have a "house challenge" every two weeks or so during the lunch hour where the students work on some trivia questions (usually pertaining to something happening in the culture at large, i.e. MLB playoffs, March Madness, the Oscars, etc.) while they eat, then there is some kind of game to go along with it.
We also have had some bigger events like a poetry recitation, talent show, and short film competition that we've introduced as competitions between the houses.
I'd definitely recommend it to other schools. It's a lot of work and takes a lot of commitment from the teachers (you truly have to own the process), but in our short time with the houses, I think it's brought a lot of our students out of their shells and pushed them to take on leadership roles. I'm looking forward to see how our system progresses.