Beethoven, alcopops and claws.
Looking back, I've actually been fairly lucky when it comes to crap prizes. There have been a few:

It all started with Beethoven (the film, not the actual composer). My dad's knowledge of rubbish puns enabling me (aged around 8) to answer a question about a 'doggy sounding composer' to win said video from the newspaper.

Hooper's Hooch. A can thereof. A friend and I luck out on the tombola stall at a village fete. Given we were about twelve we thought we were being highly naughty drinking said can. Rank stuff.

Lollipops. Hundreds of them for coming last in our local rural pub quiz. Made up for by my random luck in winning the t-shirt draw every few weeks.

But the crowning moment came in Cleethorpes (probably not too many times those words have been uttered) when I was 21. After feeding the arcades far too much of my hard earned money, I spotted a flaw in the grabbing machine. OK, so the claw might not actually grip (they never do), but I could hook it through the fake bull bars on the cuddly car and cheat. So I did. And won. And probably highly embarrassed my other half at the time with a little happy dance and chant of "IwonIwonIwonIwon".
(Picotee, Tue 3 May 2011, 17:51, 2 replies)

Curious....
Hooch never came in cans. Do you mean 2 dogs?
(robneymcplum spiced up his life on, Wed 4 May 2011, 12:40, closed)

Could have sworn it was Hooch...
either way it was some crappy alcoholic lemonade that tasted like lemon tango gone wrong.
(Picotee, Wed 4 May 2011, 15:19, closed)