MiniDungeons
it never ends

MiniDungeons and MiniDungeons 2 are games about exploring dungeons, collecting items, fighting monsters, and preferably not dying. They're made by Christoffer Holmgård, Antonios Liapis, and Julian Togelius.
They're research games that record the actions of their players, anonymize them, and send them to the game designers who use them to come up with new ways of procedurally generating dungeons by characterizing and learning from what the players do. Hopefully, this will help it to one day evolve into MegaDungeons.
They're also well suited for experiments in agent control since they come with architectures that let you simulate them easily and quickly.
Feel free to write us if you'd be interested in using MiniDungeons for research of your own. We hope to open source MiniDungeons 2 once it's ready.

There are even a few scientific papers published that feature MiniDungeons:
- Christoffer Holmgård, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis: "MiniDungeons 2: An Experimental Game for Capturing and Modeling Player Decisions," in Demo Proceedings of the 10th Conference on the Foundations of Digital Games (FDG), 2015.
- Antonios Liapis, Christoffer Holmgård, Georgios N. Yannakakis, Julian Togelius: "Procedural Personas as Critics for Dungeon Generation," in Applications of Evolutionary Computation, vol. 9028, LNCS. Springer, 2015. [Best Paper Award of the EvoGAMES track]
- Christoffer Holmgård, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis: "Personas versus Clones for Player Decision Modeling," in Proceedings of the International Conference on Entertainment Computing (ICEC), 2014.
- Christoffer Holmgård, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis: "Evolving Personas for Player Decision Modeling," in Proceedings of the IEEE Conference on Computational Intelligence and Games (CIG), 2014.
- Christoffer Holmgård, Antonios Liapis, Julian Togelius, Georgios N. Yannakakis: "Generative Agents for Player Decision Modeling in Games," in Poster Proceedings of the 9th Conference on the Foundations of Digital Games (FDG), 2014.
MiniDungeons is currently being upgraded to version 2 (screenshots above are from the new version) and is soon coming to a mobile device near you, possibly even your mobile device if it runs iOS or Android.