It's the game that just keeps on giving. Cookie Clicker released a beta version of its newest feature, which adds randomly generated dungeons and a tiny hero to venture through them in search of more cookies.
I tried out the beta, but there are still bugs to be worked out. One of the heroines, Chip, backtracks if you stop clicking the movement buttons. To try it out yourself, go to the beta here, and work your way up to 50 factories.
The beta currently features 4 heroines, Chip, Crumb, Doe and Lucky:
Right now, the hero's strength is related to how many buildings you have, but eventually there will be loot and gear, which will improve with how far you get into each dungeon. There's also a dungeon generator which will let you see what the randomly-generated dungeons look like.