I don’t use a mac, but I don’t see why linux users shouldn’t get fun toys to. So I hacked up the following two-liner that uses todo.pl and ratmenu to pop up a list of tasks, and mark one as completed:

#!/bin/sh
todo.pl | perl -ne 'push @a,$2,"todo.pl done $1" if /^#([\w]+) (.+)$/;' \
               -e 'END{exec("ratmenu",@a)}'

I dropped it into my ~/bin and bound it to C-t x in my window manager (XMonad). I love it already.