National Nanotechnology Day is an annual event featuring a series of events and activities on or around October 9th to help raise awareness of nanotechnology, how it is currently used in products that enrich our daily lives, and the challenges and opportunities it holds for the future. This date, 10/9, pays homage to the nanometer scale, 10-9 meters.
More details at the Nano.gov website.
One of the signature events is the 100 Billion Nanometer Dash: a challenge to run 100 billion nanometers (100 meters), share your pictures and videos, and get added to the online map! Universities can involve their school mascot.