be (right) down (one's) alley(redirected from are down their alley)
be (right) down (one's) alley
To be something that one is or would be very interested in. A variant of the more common phrase "be (right) up (one's) alley." Lou loves baseball, so you should definitely invite him to a game—it would be right down his alley. I love science, so studying medicine is down my alley.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.