magent is a simple but useful proxy program for memcached servers. 
see  http://code.google.com/p/memagent/
run

./magent -c ./conf/magent.conf

    * keeps connections to memcached servers
    * supports following memcached commands
         1. get gets
         2. delete
         3. incr decr
         4. add set replace prepend append
         5. cas 
    * event-driven by using libevent library
    * supports ketama algorithm
    * backup servers farm
    * unix domain socket 

 fix some bugs
1 block when the backend memcached down
2 ketama arithmetic  wrong