Staying Overnight in a Classmate's House

In order to prepare for a test the next day, I stayed overnight in my classmate's house last Monday. In the beginning, we studied together, going over one lesson after another. Later, however, we both felt tired, so we started to play computer games. We promised to play only half an hour, but we had such a good time that we played on and on until dawn. No wonder we both failed the test the next day.