A Web Quest is “an inquiry-oriented activity in which some or all of the information that learners interact with comes from resources on the internet, optionally supplemented with videoconferencing” (Bernie Dodge, the originator of WebQuests).
WebQuests are based on constructivist learning theory and have been a part of project-based learning and teaching in mainstream education for some time, but they also have a multitude of applications in ESL/EFL, both in ESL/EFL classes that are focused on content/or theme-based learning and in teacher training.