Triple XP in RDR...

So after a bit of co-op in RDR, me and a friend went into free roam and got a game alert saying all XP is being tripled. It was true, but after about an hour we got a message saying it was over. I'm wondering if this is a daily/weekly thing or was it just pure luck that we stumbled upon it today.

Either way it's nice of R* to do stuff like this :D

Cool. Should have played online.

Dang it. RDR is showing up in the mail soon, and I missed the triple XP. Well, knowing R*, something else awesome will happen after I get it.

It's done this to me twice. I like it when it does this.