Here is something I found to be quite an interesting use of the time. I constructed a little periodic table “study hall”. Basically, the game displays random elements that is set to be defined by the user. The game presents the element context – it's up to the user to see if they know them.
There are two display options. By default, both the atomic number and element name are displayed. If you want to see if you know an element's atomic number and/or name for that atomic number, you could press the appropriate button to yield your desire. Basically, it's up to the viewer to see if they superiorly know these elements, either by atomic number or element number in one of these definitions' absence.