What's the punchline......

I was having a cheeky pint of Westfold Wheat Ale in The Rider's Rest tavern in Snowbourn, Rohan. Plenty of nags outside and their riders getting merry by the open fire. At the bar I made a totally innocent tongue-and-cheek quip about why the villagers were too preoccupied with the annual Horseshoe Toss competition, where the prize is traditionally a night of passion with the daughter of the local commander, to respond to Theoden King's call for reinforcements at the Battle of Minas Tirth. The natives didn't take it well and within seconds I was getting carried out and thrown into a manure heap, much to the amusement of the punters at the veg market.

As I was getting the old 'Grima Fling' out the front door, I overheard a quintet of horse lords sharing jokes. One said: "so an elf, a dwarf, and a man, are crossing the Riddermark.....". I was face-deep in a Rohan's finest 'Brego Briquettes' long before I could hear the end to it.

Does anyone know it? How does the joke end? I really need to know.