Simple userscript that adds a pulldown menu with dailies and countdowns for same.
Modified version of the original script (http://userscripts.org/scripts/show/158306), which is no longer maintained as of early 2013. This version adds only minor features, and a number of dailies omitted from the original.
More features to come, with the disclaimer that I'm not a web developer. :)
Installation instructions via the original author: http://www.reddit.com/r/neopets/comments/17tatk/i_wrote_a_firefox_plugin_to_remind_me_to_do_my/c88pzyn (except, of course, use this userscript instead of his on userscript.org).