The video ahead is a little bit spoilery if you haven't seen The LEGO Movie. Some of the jokes might make a bit more sense if you've seen the movie. But it doesn't spoil the ending or anything, and it's pretty hilarious even out of context, so...
Just because a movie is animated doesn't mean there can't be bloopers, right? The above video treats LEGO like a live-action movie in the way it shows a sequence of outtakes and at least one line-o-rama moment, courtesy of Will Arnett's Batman. The best part is at the end when Emmet and Batman are talking about how great it would be to have some kind of backpack with just arms to rest against. Not a whole chair. Just the arms and the back. Genius.
I also loved the moment where the set fell during Unikitty's scene. Her face right afterward is pretty priceless...
Another great moment is when Morgan Freeman's Vitruvius is tossing script pages all over the floor. Speaking of Freeman, WB just released this video, which has the actor jokingly questioning why they'd ask him to play a wise, benevolent wizard.
He did nail it.
One of the things that's so great about The LEGO Movie is that there are a lot of little jokes and nods worked into the story. So many, in fact, that you might have missed some. If you've seen the movie, check out our feature, which looks at 9 cool things you might have missed here (CONTAINS SPOILERS). And here's a tenth item to add to that list. If you look closely at the instructions that Emmet's using near the start of the movie, you'll see that it's designed a bit like a LEGO box:
Most notably where the age-range and number is listed. Here's an example of a LEGO box for comparison's sake.
Some of the items featured in Eric's list are a bit more spoilery though, so hold off on looking if you haven't seen the movie yet. And go see The LEGO Movie, it's awesome.