Recently we ran a simple memory test experiment, called sentence recall, in which participants were asked to recall sentences that they had just seen on the screen. Many participants, especially non-native English speakers, made various deviations in their recalled sentences. Some deviations represent alternative ways to express the same meaning, but others suggest that there are missing pieces in the participants' language knowledge. The deviation data, on the one hand, can provide individual users valuable feedback on their language usage patterns that they may never notice, on the other hand, can be used as training data for automatically discovering language usage patterns in a subpopulation of language learners. This paper presents our attempts to create an enjoyable sentence recall game for collecting a large amount of deviation data. Our results show that the game is fun to play and the collected deviation data can reveal common language usage patterns among non-native speakers.