router.js

// routes = [ [/test/, function(url){ console.log(url) }], ... ]

setInterval(function h(r){if(h.l!==(h.l=location.hash))for(r in routes)routes[r][0].test(h.l)&&routes[r][1](h.l)},10);

Well, if you don't care about overwriting events, you could drop the addEventListener entirely and, as long as the code runs in the DOMWindow context, bind directly to onhashchange. You could also save 5 more bytes by letting h, k and r leak into the global scope.

Also, the semicolon is pretty pointless...

this.onhashchange=function(h,k,r){h=location.hash;r=routes;for(k in r)r[k][0].test(h)&&r[k][1](h)}

^^ Yeah, but that's gross, :P