|Location(s)||Portland, Oregon, USA|
|Years active||Since 2002|
|Participants||Over 100 (as of 2005)[dated info]|
Participants carry their bikes on MAX Light Rail to the Washington Park station next to the Oregon Zoo. From there, participants take the elevator to the surface and then ride their bikes down the hills in the vicinity. This process is often repeated several times throughout the night.
|“||The people that are going 35-mph-plus have backgrounds in BMX, mountain biking, bike messengering or downhill skateboarding. I don't know that people showing up for the first time understand this.||”|
—Zoobomber Mark Verno in August 2005
There is an emphasis on unusual bicycles, first and foremost the children's bicycles or "minibikes," but extending to tall bikes, swing bike,  choppers, non-functional bicycles, skateboards, longboards, etc. The Zoobombers are made up of a wide demographic, with a tendency towards young adults. The event is treated in a very lighthearted fashion, including a large amount of socializing between rides. Riders often dress up in costume or decorate their bicycles. Parents have brought their children on rides, and a legally blind person "The Blind Bomber" regularly attends (on a tandem bike, behind a sighted rider). Though not technically a race, there is some prestige in getting down the hill first. However, there is never shame in getting down the hill last, as safety and fun are what is encouraged, not going fast. The participants espouse a "pack out what you pack in/leave no trace" philosophy in an effort to maintain cleanliness in the areas where they congregate. Zoobomb tries to be a positive force in the community by providing a safe environment to have a good time and to support bicycle advocacy and alternative non-polluting transportation.
Though many riders bring their own bicycles, the participants maintain a "Zoobomb pile". This is a tower of minibikes anchored to a bicycle rack at the Zoobomb meeting point. These are spare bikes that are used as loaners for would-be Zoobombers who don't have their own bike. The pile has become a local landmark.
There are several annual events hosted by Zoobomb organizers and participants, including:
- Zoobomb Century in June
- MiniBikeWinter in February
- Zoobomb Summer Olympics (aka BiffDay) in August
- Alleykitten Invitational
- Cycling in Portland, Oregon
- Portland Urban Iditarod
- Kinetic sculpture race
- Shopping cart race
- Hartley, Brandon (August 24, 2005). "Still Bombing after all these years". Willamette Week. Retrieved 2011-11-06. "The club began locally in 2002 when Zach Archibald, fresh off a bus from Texas, met a few people who rolled up on mini-bikes outside Rocco's Pizza at Southwest 10th Avenue and Oak Street. They eventually took Archibald up to Washington Park to go bombing, and the club fell together once word got out. Zoobombers are mostly teenagers and twentysomethings, with an occasional older rider thrown in. Skateboarders, longboarders and riders of "assacres" (low-rider scooters) have also joined in the weekly run, which routinely draws over a hundred people and has lured riders from as far away as Britain, South America and Japan."
- "Portland's Bike Culture Creates Market". OPB. January 9, 2008. Retrieved 1 October 2010.
- "Close-up: Zoobombing in Portland, Oregon". BBC News. 5 November 2011. Retrieved 2011-11-06. "Some of the bikes are left chained up in a pile in the city centre, which has itself become a local landmark. The ride, often repeated several times in an evening, starts with a journey on Portland's light rail system then a hike to the top of a hill, near the city's zoo."
- "TWO-WHEELED TERRORISTS". The Portland Mercury. February 27, 2003. Retrieved 2010-10-01.
- "Zoobomb pile will become official public art". BikePortland.org. October 2, 2007. Retrieved 2008-08-14.
- "Sam Adams at Zoobomb Pile Dedication". The Oregonian. March 28, 2010. Retrieved 2011-11-06. "Mayor Sam Adams hangs with the Zoobomb crew at the dedication of the new Pile."
- Frochtzwajg, Jonathan (August 11, 2010). "State police lose tolerance with dangerous Hoodbombing". The Sandy Post. Retrieved 2010-10-01.