A foil blowout is the correct name for the party favour consisting of a plastic tube with a rolled up piece of plastic-covered tinfoil on the end that's rolled up tightly, has the plastic slightly tighter on one side than the other so as to roll itself up naturally, and is perforated slightly at one end. Certain more de luxe specimens also have a little feather on the end, and usually they are brightly coloured.
When you blow into them, they unroll and make a noise which is impossible to describe but could well be rendered in text as, "fwoooommmp!"
It took me ages to find out what the correct name of these things are. I always knew them as "those things you blow in at parties," and indeed, when growing up in the 1990s as a kid I'd be invited to peoples' birthday parties and there'd always be these alongside the jelly and ice-cream. Nobody knew what they were called. I also recall playing a text adventure called "Dead or Alive" which was penned by a gent called Kevan Davies better known now for the "Urban Dead" browser game and about which he doesn't like to talk. In this game, you find "one of those things you blow in at parties" and, of course, it has no real use so you end up carting it round the entire game.
I asked all my friends when at secondary school what one of these is called because I couldn't find out whatsoever. They were bemused. "One of those things you blow in at parties?" said Alexander. "Erm, women's crotches?" (I wish I got invited to those sorts of parties.) Others were more snarky - "Blow jobs!" said another pal I had. Fnarr fnarr. However with much googling I found out that their real name was this, foil blowouts.
So there you have it. You have all just learnt something that absolutely nobody required you to know.
(IRON NODER 2011, 22/30)