Hey Joel,
 

You're right, it doesn't match /media/foo/bar. The reason is simple: the syntax for routes, as defined by Sinatra, is not pure regex, and avoids matching a slash on purpose.[1]

The idea is that you could declare a variable being there, without providing a name, and then splat() returns it.
 

Since the route syntax doesn't cover regexp.
 

If you know the level, and you want to be explicit, you can try the default route syntax: '/media/*/*'.
However, you will most likely prefer a regular expression (which you tried earlier), and Dancer allows that very easily since Perl considers regexes as first class:
get qr/.../ => sub { ... };

We prefer to wrap qr() with something other than slashes, so we don't get into a backslash fight:
get qr{ / media / (.*) }x => sub { ... };

Enjoy!

[1] As they say in Microsoft: "it's a feature, not a bug!"