Classroom teachers may not initially consider games as opportunities for students to engage in deep mathematical thinking. However, this article reveals how a second grade veteran teacher used Attribute Trains, a game adapted from NCTM Illuminations, to foster his students' thinking related to key ideas within the Standards for Mathematical Practice (SMP) from the Common Core State Standards for Mathematics (CCSSM) (CCSSI 2010). Incorporating mathematical games into the instructional period can be a valuable use of class time by providing a context for students to explore and manipulate mathematical ideas when teachers incorporate higher-order discussion questions that engage children in reflection and representation. When teachers construct guiding questions that encourage students to "reflect on and represent the mathematical ideas that emerged in their play" (NAEYC/NCTM, 2010), they present students with opportunities to use critical thinking while emphasizing content, all in the context of having fun.