The free FFMPEG video utility can do this pretty simply using a command line. This works in Windows and Linux and probably MacOSX as well.

ffmpeg -i input.avi -vcodec copy -acodec copy -ss 00:00:00 -t 00:30:00 output1.avi -vcodec copy -acodec copy -ss 00:30:00 -t 00:30:00 output2.avi

ffmpeg -i input.avi -> your large video file. This can also be mp4.
-vcodec copy -acodec copy -> copy both video and audio.
-ss 00:00:00 -t:00:30:00 -> sets a start time and end time for the first video that will be saved as output1.avi.

This will create two 30 minute files from a 60 minute file.