Notcurses is ok, not great.

Tickit[1] is much nicer, and comes with what is possibly the only good way of reading modifier characters from a terminal (seriously).

Alternately, if you're ok with not running in a terminal, check out bearlibterminal[2].

1: http://www.leonerd.org.uk/code/libtickit/

2: http://foo.wyrd.name/en:bearlibterminal