There's lots of stuff yet to do!  This is just scratching the surface:

ev:
 - rework the internals; two queues is maybe too much
 - timeouts support
 - write more 'backends' for kqueue and epoll

fcgi:
 - I'm a sucker for running stuff behind httpd.

http:
 - find a way to associate custom data to a request for asynchronous
   re-entering (and eventually free the custom data too!)
 - notify unexpected disconnection when re-entering?  (i.e. notify the
   route function when they set res.done = false)
 - http keepalive?
 - actually parsing headers.  do we want to expose all of them?
 - parse body contents.

http::session:
 - a custom module for session handling would be nice.  Or just use
   Authorization header and be done with it?

http::websocket:
 - another would be nice to have :)

gemini:
 - Yes, I'm serious!  A gemini module to serve stuff via gemini (w/
   libtls bindings?) would be cool and probably fit shinsha well.

sqlite:
 - write the bindings.  Maybe drawing some inspiration from
   https://github.com/crawshaw/sqlite (and the sqlitex subpackage)
   which is my favourite sqlite binding for Go.

template:
 - write (how?) some kind of template processor with the asynchronous
   http module in mind?