As experimentation in the behavioral and social sciences moves from brick-and- mortar laboratories to the web, new opportunities arise in the design of experiments. By taking advantage of the new medium, experimenters can write complex computationally mediated adaptive procedures for gathering data: algorithms. Here, we explore the consequences of adopting an algorithmic approach to experiment design. We review several experiment designs drawn from the fields of medicine, cognitive psychology, cultural evolution, psychophysics, computational design, game theory, and economics, describing their interpretation as algorithms. We then discuss software platforms for efficient execution of these algorithms with people. Finally, we consider how machine learning can optimize crowdsourced experiments and form the foundation of next-generation experiment design.