mknod backpipe p; while nc -l -p 80 0<backpipe | tee -a inflow | \
nc localhost 81 | tee -a outflow 1>backpipe; do echo \"restarting\"; done

Listen on localhost:80, forward to localhost:81 and log both sides of the conversation to outflow, automatically restarting if the connection dies.

It can be useful to not only know what has gone to stdout and stderr but also where they occurred with respect to each other.
Allow stderr to go to err.txt, stdout to out.txt and both to mix.txt

((./program 2>&1 1>&3 | tee ~/err.txt) 3>&1 1>&2 | tee ~/out.txt) > ~/mix.txt 2>&1

Get DVDs playing on Ubuntu Gutsy by installing libdvdcss2.

echo "deb http://packages.medibuntu.org/ gutsy free non-free" | sudo tee -a /etc/apt/sources.list
echo "deb-src http://packages.medibuntu.org/ gutsy free non-free" | sudo tee -a /etc/apt/sources.list
wget -q http://packages.medibuntu.org/medibuntu-key.gpg -O - | sudo apt-key add - && sudo apt-get update
sudo apt-get install libdvdcss2