Science Fair PRoject???!!!!?

OK IM RUNNING OUT OF TIME 4 MY SCIENCE FAIR PROJECT AND BARELY KNOW WAT IM GONNA DOE IT ABOUT!!! so does anyone have an idea for a project that haz to do with experimenting on mice and has to do with chemistry or biology (no blood plz =O) ive looked over the internet ...but i cant seem to find anything my grade level which is like about 8th or 9th grade work so CAN SOMEONE HELP.!!