In 's Up, When Richie and Eddie are on the roof, the first scene has them looking through a big telescope which on a tripod between them. As soon as the joke is done, the Telescope is gone and never mentioned again.
When Eddie goes down to fight the looters the sky is totally blue. But all of two minutes later when he comes back on the roof, the sky is totally gray.
When Richie and Eddie are on the roof and Richie starts his rain dance, he pulls the hem of his trousers up to around his shins. He then starts and stops and at this point the right hand trouser falls back down his leg. Then straight afterwards in the long shot you can see that it's back up again without him pulling it up.
Richie curls his right hand into a fist to punch Eddie and Eddie tries to dodge it. When Richie punches Eddie over the railing, he uses his left hand.
Richie is looking at the video "Big Jugs" which is supposedly a history of pottery in the 19th century. However we can clearly it's a cert 18 on the box, it's unlikely the subject matter would have an 18 certificate.
After Ritchie's face is dirtied by a bird you can see the arm of a crew member at the bottom left of the screen.