This has probably been done before, but I can't be arsed to search for it.
I've just read GM's Incredibly s*** adverts thread and wanted to have a little think about some of the belters over the years. Obviously Guiness springs to mind, both the dominos one and, even better, the travelling back in time one. I like the one where the birds can't fly, and there's a banging tune you try to whistle for hours afterwards, but can't, because it's too difficult. Cillit Bang is 'bang' on, and there was a great egg card advert where a woodpecker flew past a man's head and he said 'Whoah. What's in YOUR wallet'

My favourite ever ad was a Natwest one where this little cartoon dog went off getting into little scrapes and there was a quality song in the background "Every step I take *WOOF WOOF* I make a new friend"
No-one mention the drumming gorilla.