The intergroup prisoners' dilemma maximizing difference game (Halevy et al. 2008) implemented in the python-based oTree framework (Chen et al. 2016).
Chen, Daniel L., Martin Schonger, and Chris Wickens. "oTree—An open-source platform for laboratory, online, and field experiments." Journal of Behavioral and Experimental Finance 9 (2016): 88-97.https://doi.org/10.1016/j.jbef.2015.12.001
Halevy, Nir, Gary Bornstein, and Lilach Sagiv. "“In-group love” and “out-group hate” as motives for individual participation in intergroup conflict: A new game paradigm." Psychological science 19.4 (2008): 405-411.https://doi.org/10.1111/j.1467-9280.2008.02100.x
The oTree core libraries are here.