Odd, glitchy shadows (Blender Internal) Uploaded an unlisted video of it on youtube, happens at 00:05.

If you notice, the shadow of the blue shirted guy's head is blocky and very glitchy. I have no idea what caused this. Here are my render settings:
24fps
AAing turned on at 8, full sample
256x256 tile size
PNG, 90% compression
720p 100%

I just need someone to explain this. Thanks.
The blocky shadows are either caused by a low resolution shadow buffer or your object doesn't have enough geometry for the shadow to disperse and appear smooth.

Go to the lamp and under Shadow, increase the size value of the lamp. While you are there, try tweaking the other setting as well to get even better results (hover over the tooltips to see what they do). If not, try subdividing the model a bit, notice the shadow the heads casts on the flat chair shape behind is smooth.
Size: 128

Size: 1024