Jess Ranard Underwear Run
An annual event started in 2013 by everyone's favorite MasterBaker, Jess Ranard, in honor of her birthday, body positivity, feminism, being queer, and JUST BEING GODDAMN AWESOME. Taking place on April 15th (or a day close to that) near midnight, attendees strip down to their underwear (or whatever they feel comfortable with) and run through several areas of campus, especially those occupied with people. It's especially fun on weekdays, because then you can watch all the people in the library go "wtf?" as you run by in your skivvies.
The 2015 Jess Ranard Underwear Run was notable for featuring a Tunak, one of Sigma Nu's traditions. It was requested by Carly Taylor and implemented by Matt Sugai. It was a first time Tunak for many people, and they definitely got a kick out of it.
The 4th Annual Jess Ranard Underwear Run of 2016 was notable for being the first incarnation not run by Jess herself, as she had graduated, finished post-bacc obligations, and moved to Washington D.C. Jess has since promised to organize another underwear run when she visits in May. :)