The chances are that if you've hit Destiny's soft level cap then you are almost certainly hungry for engrams. The gear grind that makes up the endgame in Bungie's "shared world shooter" means that every time one of those glowing crystal prisms erupts from an enemy corpse, you make a beeline to it with ravenous haste. The trouble is that it can take ages to get hold of the more valuable blue variety and you're by no means guaranteed to get that sweet new leg armour you need when the drop finally comes.
If you're looking for somewhere you can tip the odds more in your favour, though, then you might want to check out a particular spot in the Cosmodrome in Old Russia. Uncovered over the weekend (thanks Kotaku), this one cave in the Skywatch region of the map offers just the right circumstances to quickly acquire a whole lot of engrams - at least until Bungie wakes up and does something about it.
"The magic cave" as it's become known can be found by heading through the factory where you first fought the famous wizard from the moon. Launch a Patrol mission in Old Russia and head in that direction: upon spawning, go diagonally ahead and left, under the bridge, across the dip and you should see the building on the far side of the valley that sprawls before you. Cross to it and then navigate the corridors at pace - if you're a decent level then you should be able to sprint and lift past all the Hive enemies.
At the wizard's location, go up onto the raised area and then exit left through the room with the Fallen Captain. A few twists of the corridors beyond and you should be out in the open. Now go straight ahead towards the area where the Fallen and Hive are fighting each other. You won't need help finding the cave. It's located in the base of a small cliff that a dome-shaped building sits atop, but there will be other players camped around it to help you identify it.
The trick to farming engrams here is to hang back just far enough not to impede the Hive enemy respawning behaviour. There are lumps of concrete in the snow directly opposite the cave entrance and you want to be three or four back from it (there's one that's shaped like a ramp that is a good yardstick), far enough away that you get a mixture of Acolytes and Thralls spawning inside it. Then just mow them down as they spawn inside the cave. Just train your sights on it and they will pop up on a timer. They are low level, so you should be able to slaughter them.
Aaaand repeat. That's it. The cave will soon fill up with ammo drops and engrams. You may groan every time you see a green one, but remember that you will gain valuable weapon parts for dismantling anything you don't want. Before long, the process of repetition should yield plenty of blue as well. Nip in occasionally to hoover up and restock on ammo, but do be polite to other nearby farmers by not clogging up the cave spawns by doing your inventory management in its jaws.
One other thing to look out for: every so often, you receive a little notification in the bottom-left that your enemies are fighting each other. This is a cue for a massive increase in the volume of enemies spawning in and pouring out of the cave, which can quickly become overwhelming - not least because the Fallen increase their spawn rate over on the right of the map, too, and proceed to attack you from that direction as well. Don't worry though - if you die then the engrams will still be intact and you should respawn close by.
Now get in there before Bungie patches it out.
Update: Ian created this video guide "to help people" and not at all so he could farm his own loot.