Lightbringer

Okay... so this was moved from Q&A to EotN Explorer's? o.O Something not quite right, methinks.

Aaanyway. The last double rep weekend was sometimes in autumn last year, and I think they only want one per year, what with the 50,000 minutes of favor it produced. So you might have to wait longer. Not 100% sure that it was a LB/SS weekend, but it was a double-rep one

Doing LB/SS runs in Sulfurous Wastes is a (relatively) fast and steady way of getting points as well as loot. I paid for Ancient Armor out of the cash gotten from maxing LB and SS.

I don't think the OP was asking for advice on farming for the title. If this is a first-time player who has just reached the Desolation, suggesting point farms in HM is not very helpful. They need to get the rank up to acquire the LB skills as part of playing the game.

@OP: First, I would suggest doing as many of the Vabbi side quests as you can. Don't skip anything. Many of them reward 10-15 LB points, and you should be able to get upwards of 150 points just from quest rewards.

Second, while you do those quests, always look for Whispers Informants at shrines and take the bounty they offer, which will usually be an Elemental Hunt. There is generally a LB bounty offered near any area where you encounter Djinn and Roaring Ethers. (Remember to do the same as you explore the Desolation, where you can get bounties for Elementals, Graven Monoliths, and Margonites.)

If you've already done most of the quests but have not been killing under bounty, then you can do a bit of farming to get your rank up. The easiest way is to exit from Dzagonur Bastion into Mirror of Lyss, take the bounty at the shrine near the portal, then kill all the elementals (9 groups of 4 foes) on the east side of the map, heading toward Honur Hill. Each run only takes about 10 minutes and gives 72 points. Another option is to clear the elementals in the Hidden City of Adashim. Get the bounty at the shrine where you first enter the City.

A good way to get LB points is by being ran in DoA. When you finish nighfall, I would say find a runner for gloom. I find it much faster there than in Sulfurous Wastes.

You can also just kill stuff in the realm of torment. Think nearly all bounties there are for LB. The domain of secrets has tons of stuff to kill, at least 200pts in nm and over 800 or so in hm.

finish the game and do DOA, or vanquish Vabbi areas
DOA will give you insane points

Gloom gets around 3-5k per 30 minutes with a decent runner. So you could get r8 lb in 10 hours. Making at least 6k per run x 20 runs. 120k cash doesn't sound that good, but hey you were just looking for lb points.