This paper presents MyBestQuery, a serious game designed to collect query reformulations from players. Query reformulation is a hot topic in information retrieval and covers many aspects. One of them is query reformulation analysis which is based on users' session. It can be used to understand user's intent or to measure his satisfaction with regards to the results he obtained when querying the search engine. Automatic query reformulation is another aspect of query reformulation. It automatically expands the initial user's query in order to improve the quality of the retrieved document set. This mechanism relies on document analysis but could also benefit from manually reformulated query analysis. Web search engines collect millions of search sessions and possible query reformulations. As academics, this information is hardly accessible for us. MyBestQuery is designed as a serious game in order to collect various possible reformulation users suggest. The more long-term objective of this work is to analyse the humanly produced query reformulation in order to both analyse manual query reformulation and compare them with the automatically produced reformulations. Preliminary results are reported in this paper.