verticalgrain/cookbook/master/.htaccess

ExpiresActive On
ExpiresDefault A0

# 1 YEAR - doesn't change often
<FilesMatch ".(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav)$">
ExpiresDefault A31536000
</FilesMatch>

# 1 WEEK - possible to be changed, unlikely
<FilesMatch ".(jpg|jpeg|png|gif|swf)$">
ExpiresDefault A604800
</FilesMatch>

# 3 HOUR - core content, changes quickly
<FilesMatch ".(txt|xml|js|css)$">
ExpiresDefault A10800
</FilesMatch>

On Github License