With the Tumbling Boulder on a roll of 2 - 6 does the Boulder then remain on the new space to be encountered again on a future turn? In essence, does it keeps tumbling until someone rolls a 1 when encountering it? I know it doesn't explicity say to discard it, but most Events are discarded after their effect expires.

Sorry, not paying attention. I meant to post this in the questions forum.

In our group we discard it afterwards, but I don't know if thats the right way to play it :/

We do the opposite - we let that boulder keep tumbling until it is destroyed.

It sometimes even tumbles out of the Highlands and onto the main board!

Well, doesn't the card say that all cards on the spaces it tumbled over are discarded?

Since it's on one of these spaces as it resolves, I'd say discard it (as well as the other cards).

Tumbling boulder is only discarded if you roll a 1.

with a 2-6, it destroys the other cards on the space, but not de boulder itself.

It never occurred to me that it might keep rolling, but I like it! I'll introduce that interpretation next game.

Well, Velhart, I don't know about your card, but in my language it's written on the card that all cards on those spaces get discarded - and since Tumbling Boulder is on one of those spaces...