Cocking a snook at the Organising Committee
My favourite is by the bookmakers Paddy Power, whose ad at the top of the page trumpets their sponsorship of an egg and spoon race in London, France.
More stories here at The Drum, who also host a great Fauxlympics: Olympic-based ads that probably shouldn't run, possibly won't run--but would be bloody good if they could run. More here, here and ... gosh, just keep looking around their site for even more.
[Hat tip Julian D.]