As usual, the definition of "weekend" in LotRO is pretty generous, with the offer active now and continuing through the 25th. You'll find a few bonuses while you're in Middle-earth as well. Travel at all the stable-masters is free, and there is a 5% XP boost for the duration of the weekend. (Even better, that 5% bonus stacks with rest XP!)
If you've been away from LotRO for a while, take some time over the next few days to check out what's new, on Turbine's dime!