Yeeeah. Aaaaahm American. I'm goin' owt schaaapping.
You guys pronounce vowels like you're trying to open your mouths as wide as humanly possible!
Edit: The actual linguistic term for this is "Canadian Raising". We contract our vowels before voiceless consonants (consonants where your vocal cords are not vibrating - such as the 't' in "about").
Here are some samples of Canadian Raising. It's different than the way americans speak, but it's in no way "oot and aboot"!
http://www.gazzaro.it/accents/files/CanRaising.html
http://www.yorku.ca/twainweb/troberts/raising.html
I think the best example is the "lout vs. loud" one. The raising only happens in "lout" because the vowel sound is followed by a voiceless consonant (where the vocal cords do not vibrate), unlike "loud" which ends in a voiced consonant (vocal cords vibrating).
This linguistics lesson has been brought to you by The Crispy Delicious.