In this study, I investigated the effectiveness of a creativity-support system that I developed in the level editor of a learning game called "Physics Playground" on improving college students' creativity. Moreover, I investigated the validity and reliability of an in-game assessment of creativity to measure students' creativity. Participants (114 college students from Florida State University) were randomly assigned into one of the four conditions: (1) "Inspirational" receiving inspirational-only supports (i.e., access to a website with thirty example levels, a brainstorming tool, and a remote association activity including three random inter- and intra-domain words); (2) "Instructional" receiving instructional-only supports (i.e., specific instructions to first design as many levels as possible, then pick four of the levels, and finally enhance those four levels using a tool called SCAMPER); (3) "Both" receiving both inspirational and instructional supports; and (4) "No Supports" which did not receive any of the supports mentioned above. Using an Exploratory Factor Analysis, correlational analyses, a reliability analysis, and multiple Analysis of Covariance (ANCOVA) analyses, I investigated the research questions of this study. Results showed that the in-game measure of creativity is valid (has both construct and convergent validities) and reliable. Moreover, the Both condition showed to be more effective than the other conditions both on the external measure of creativity and on the in-game measure of creativity. Implications of the findings, limitations, and future research are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]