Here’s a little snippet that you can stick into your .bashrc file. It creates a hash of the hostname and uses that to color the ps1 variable, so that hosts with similar names look different when you are shelled into them.

function colorps1() {
    word=`hostname --short`
    hash=`echo "$word" | md5sum`

    fullstr=""
    for l in `echo $word | sed 's/\(...\)/\1\n/g'`; do
        control=""
        endcontrol='\[33[00m\]'
        case "${hash:0:1}" in
            0)
            control='\[33[1;30m\]'
            ;;
            1)
            control='\[33[0;31m\]'
            ;;
            2)
            control='\[33[0;32m\]'
            ;;
            3)
            control='\[33[0;33m\]'
            ;;
            4)
            control='\[33[0;34m\]'
            ;;
            5)
            control='\[33[0;35m\]'
            ;;
            6)
            control='\[33[0;36m\]'
            ;;
            7)
            control='\[33[0;37m\]'
            ;;
            8)
            control='\[33[1;30m\]'
            ;;
            9)
            control='\[33[1;31m\]'
            ;;
            a)
            control='\[33[1;32m\]'
            ;;
            b)
            control='\[33[1;33m\]'
            ;;
            c)
            control='\[33[1;34m\]'
            ;;
            d)
            control='\[33[1;35m\]'
            ;;
            e)
            control='\[33[1;36m\]'
            ;;
            f)
            control='\[33[1;37m\]'
            ;;
        esac
        hash=${hash:1}

        fullstr="$fullstr$control$l"
    done
    fullstr="\[33[1;31m\]\\u@$fullstr$endcontrol \[33[1;34m\]\W \$ \[33[00m\]"
    export PS1=$fullstr
}

colorps1