Multiple redirects / rewrites within one VirtualHost group
RewriteCond %{HTTP_HOST} ^(www.)?domain.com$ [NC]
RewriteRule ^$ /special-landing-page [R,L]
post what you've tried.
Use the following in the config file to generate a rewrite log to see just what is happening
RewriteLogLevel 9
RewriteLog /tmp/rl
Disable this afterwards as it can be quite server intensive on a busy site.