Given the importance of creativity for both personal and societal achievements, there have been consistent efforts to stimulate creative ability. But an important environmental factor-blue (i.e., short wavelength) light - has been relatively unexplored to date. Blue light improves a number of cognitive processes (e.g., attention, working memory and sleep) known to influence our creative abilities. In this study, we investigate the effects of blue light on enhancing creativity in tasks and compare it to the effects of walking, which has been shown to stimulate creative ability. Based on data from 21 participants over 2 weeks, we found that blue light resulted in a 24:3% increase in convergent thinking ability, while walking improved divergent thinking by 18%. We discuss the implications of the findings within the context of UbiComp research. To the best of our knowledge, this is the first systematic examination of the impact of blue light on convergent and divergent thinking ability.