I am certain that there are other ways/tools to perform this, but a quick way:
#du -k / | sort -n | tail -10
This will list the 10 largest files.
You may want to check the man page of the
find command, but you can also try:
#find / -size +10000000c -xdev
this will list anything over 10 Meg.
If this is a cronic
problem, then consider cron as an option and have one of these tools run and spit that output to file.