I've had Orff I training, but even before I was officially certified in Orff, I have always liked using xylophones. I highly recommend taking Orff classes and/or attending Orff workshops. They have such hands-on ideas for getting the students actively involved in music making.
Anyway, this post is about how I leave my xylophones set up all of the time. I do that so it's easy in a 30-minute lesson to have everyone take a turn on xylophones in a short period of time.
I can point and say: "Johnny, xylophone 1. Susie, xylophone 2..." Students go to the xylophones, pick up their mallets and wait.
I even sing a little ditty: "Pick up your mallets; don't play yet!" - and students usually start singing it with me. They know if they play when they aren't supposed to, they lose their turn.
I used this straight-line configuration for several years - and just last year I tried something that I liked even better (no photo, sorry). I put the xylophones in groups of 2 or 4 around the room at different stations. That caused less bottleneck and allowed for students, who are sitting in a U-shape on risers, to see xylophones without turning all the way around.
Each xylophone has a little eighth note with the number of the xylophone on it, both on the front and on the top.
By the way, while I'm talking about xylophones, I love these rolling stands. I have 2 of them: one for my BX (bass xyl), and one for my BM (bass metallophone, which I don't use very much - something about the timbre bothers me). They are also adjustable to use for the AX and AM (altos), but I didn't have enough money in the budget to buy that many. :-(