Here is a simple little hack to put the holiday spirit into your command line. Paste this into your command line, and enjoy. :-)

cd
mkdir bin

cat >bin/prompt_command <<EOF
c0=\$'\\e'[31m
c1=\$'\\e'[32m
normal=\$'\\e'[0m
pcolor="c\$(( \${PROMPT_NUMBER:=0} % 2 ))" 
PS1="\${!pcolor}\\h:\\w\\u\\\$\${normal} " 
let PROMPT_NUMBER=PROMPT_NUMBER+1
EOF

export PROMPT_COMMAND=". prompt_command"