Flash Bash
Java, ActiveX, Flash, SilverLight,... the pattern goes on.
But let us not forget why they became so popular in the first place - because of the horrifically broken, limited and outdated HTML specifications, that hamper any attempt to put pixels on the screen at a specific location.
The ancient 'HTML' way of doing things (by positioning graphics at the text cursor) has driven developers, plugin manufacturers, and users, for years, to do whatever they can to circumvent it. Yet it still persists.
* And don't give me that 'different screen sizes' crap - game developers have catered for different shaped screens since games were invented.