In all four videos of PoTF Mark plays at least two roles
Late Goodbye: two (one Mark drives the car, second sings with the band);
Lift: two (objectively one Mark sitting on the chair, subjective one of six different personalities);
Carnival of Rust: two (Zoltar and Mr.Greed);
Locking Up the Sun: four (two Marks on the triangle ring, one in the crowd and one with the cone on his face, locking up the orange).

Locking up the Sun
On 11th second you may hear the whisper "Oh my God".

Gravity
1:20 - Mark says something like "I think I should say something", and then "Here we go".

Same effect in two songs
Gravity: 1:33
Stay: 2:14
Mark singes "Stay"

All The Way / 4 U
The keyboard background starting at 2:09 also can be an intro of Dawn after changing the playback speed.

Delicious
At 3:42 in left speaker one can hear anincomprehensible coughing, or unchancy whistle.

Don't Mess With Me
Is it the studio phone ringing in the end of the song?

All The Way / 4 U
Looped guitar of Ollie in the fact does not make a clean rythm loop. Fourth time is cut a bit.

Signs of Life
It used to be a title of Pink Floyd's "A Momentary Lapse Of Reason", but David Gilmour denied this variant. Instead he called "Signs of Life" first instrumental of the album.
All Poets are huge Pink Floyd fans.

3 A.M.
There is a movie named 3 A.M., bringing fame to actress Michelle Rodriguez.