The Wilhelm scream is an incredibly over-used meme - It can be funny in games and films if used correctly and subtlety, but most get it wrong and then it ends up being distracting.
3 vids with disabled embedding, yay:
Mars's Dry Ice and Dunes
Somebody converted a DeLorean into a hovercraft.
Russia is a crazy place. (First clip is sorta disgusting, you've been warned.)