The API takes advantage of the server's opaque flag support and sets its 
"complex" flag whenever the object being stored or retrieved isn't a plain
scalar. In that case, the Storable module is used to freeze and thaw the
value automatically going in and out of the memcached.

WWW: http://search.cpan.org/dist/Cache-Memcached/
WWW: http://www.danga.com/memcached/