One of the things I was planning to do but never did is installing nginx as reverse proxy in front of Apache.
nginx is present in the epel repos for CentOS, so the installation process is just a matter of:

yum install nginx mysql mysql-server phpmyadmin httpd
wget -q -O - | sh
yum install mod_rpaf
mkdir /etc/nginx/v.hosts
vi /etc/nginx/nginx.con
http {
    include  v.hosts/*.conf;
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main; 
    charset   utf-8;
    keepalive_timeout  65;
    server_tokens       off;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         off;
# Default Server Block to catch undefined host names
#    server {
#          listen 80;
#          server_name  _;         
#          root   /usr/share/nginx/html;
#          index  index.html index.htm;     }
/usr/sbin/nginx -t
    server {
          listen 80;
           access_log  off;
           error_log off;
          location / {
            proxy_set_header        X-Real-IP       $remote_addr;
            proxy_set_header        Host            $host;
            proxy_redirect          off;
            proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_connect_timeout 90;
            proxy_send_timeout 90;
            proxy_read_timeout 90;
            client_max_body_size 10m;
            client_body_buffer_size 128k;
            proxy_buffer_size 4k;
            proxy_buffers 4 32k;
            proxy_busy_buffers_size 64k;
sudo /usr/sbin/nginx -t
service nginx restart