At the Roundtable Discussion with M. Night Shyamalan
when I asked him about the Comedy / Humor in The Last Airbender, he mentioned that he "Literally took the Blue Spirit Episode and put it right into the movie".
The Blue Spirit Episode was certainly one of the coolest, so you might be interested to see some early looks at how The Blue Spirit will appear in The Last Airbender, in the trailers the only part I was able to catch a glimpse of the Blue Spirit is pictured below.
[caption id="attachment_961" align="aligncenter" width="410" caption="This shot of the Blue Spirit Appears at 1:12 of the 2nd Theatrical Trailer Release. The Blue Spirit Appears to have a large mane of hair."]
[caption id="attachment_962" align="aligncenter" width="463" caption="The Blue Spirit from Avatar The Last Airbender"]
The Blue Spirit appears to be more "bluish" as well as sporting a large mane of hair, to see this particular shot, Head on over to the Second The Last Airbender Theatrical Trailer
and watch at about 1:12.
You can also check out a couple of early action figures for the Blue Spirit.
[caption id="attachment_963" align="alignleft" width="246" caption="The Blue Spirit has already been made into an action figure."]
[caption id="attachment_964" align="alignleft" width="224" caption="The Blue Spirit Mask looks spot on."]
I'm way stoked to see the Blue Spirit on the big screen, I think it'll be an awesome scene.
Oh BTW if you're new to the series, The Blue Spirit will remain a mystery, until you see the movie, or series.