We present a prototype of a novel online platform for promoting playful learning exercises in classrooms, allowing teachers to engage with students in an interactive way. Differently from typical e-learning environments, it is the teacher, not the machine, who leads the learning activity, i.e., she is able to monitor students’ individual and aggregated answers and provide them real-time feedback. Although the platform is subjectindependent, we are currently focusing on language exercises based on standard school curriculum. Answers provided by students and validated by the teacher (or automatic assessment) could constitute, in a large scale scenario, a valuable source of linguistic annotation. The platform can therefore be seen also as a crowdsourcing system to create novel linguistic resources to be used by the scientific community in the Natural Language Processing field.