Sometimes we're all challenged with thinking of something creative to do during a discussion section.
Remember that it's not always about being "creative," but rather catering to the needs of your students – what do they need from you, the TA, at that moment. Maybe they need more review than creativity, maybe they're bored and need to be challenged…always make sure the class is focused toward what your students really need, not just what you have in your lesson plans!
Teaching Strategies: Active Learning - The University of Michigan's Center for Research on Learning and Teaching provides a list of additional resources that may be of interest.
Richard Felder and his wife co-direct the National Effective Teaching Institute, and he regularly posts and updates teaching and instructional techniques on his website.