Founded in 2004, the Xlab--more formally, the Experimental Social Science Laboratory--is a laboratory for conducting experiment-based investigations of issues of interest to social scientists. The Xlab is conveniently located in the Haas School of Business, Room S460. The Xlab is an interdisciplinary facility at UCB that supports investigators who wish to conduct experimental research. The physical infrastructure of the Xlab consists of 36 laptop computers linked through a private network. The computers can run networked experiments, as well as those based on the Internet. Xlab's human infrastructure includes experienced IT professionals, dedicated lab administrators, and a subject pool in excess of 5,000 members.