The single sees forty-four British and Irish artists of varying popularity singing their hearts out to raise money to help out sufferers of the Ethiopian famine. The video was a simply mixed shots of the artists recording their pieces- if you look about three and a half minutes in you'll see Paul Young singing what looks like "eat the world".
1989 saw another Ethiopian famine and another recording of Do They Know It's Christmas with different artists (Bananarama's Sarah Dallin and Karen Woodward are the only artists to have sung in both versions, though they have a much more prominent role in the second) under the name of Band Aid II. In my opinion, Cliff should wear those headphones more often.
Presumably Band Aids 3 to 19 inclusive didn't quite make it into the public arena for some reason, but a new bunch of artists were joined by Bono (the only member of the original Band Aid to sing in 2004's version as well) to form Band Aid 20. This version benefited from a bit more of a guitar driven sound, but also included Dizzee Rascal in a special, new, pointless, cringeworthy rap segment which spoils the song and makes sure that the original is unarguably the best.