This is a nice little bit of shell magic I discovered today:
trap true TERM kill -- -$$
The first line means that when the shell receives a TERM signal, it executes true. The normal behaviour would be to kill the process, so this means that the shell is immune to people sending a TERM signal to it. The second line sends a TERM signal to the process group (- is the modifier to indicate a the process group of the PID, not just the PID) of the current process ($$).
The end result? Everything spawned by this script which hasn't gone and re-parented itself is killed: the ultimate in cleanup.
NP: Dedications, Klimek