I believe this was posted once upon a time but I can't remember where it was posted. I had some requests for the macro so here it is;

/run if IsMounted() then Dismount() return end local t if IsFlyableArea() then t={1,9,25,40} else t={2,4,12,17,18,19,21,27,33,34,35,36,38,39,42,43,44,45,46,48,52} end CallCompanion("MOUNT",t[random(#t)])

It isn't very effective in Dalaran - to the point of not working. It tries to load up a flying mount which you can't do there. But everywhere else you'll be fine. The first set of numbers is your flying mounts, the second set is for your ground mounts. To get the mount number count from the top left on the first page and count to the right.

[01][02][03][04][05][06]
[07][08][09][10][11][12]

Continue counting on the following page starting at 13 on the top left.

That's it - enjoy!

Thanks!