Operation Ivy was a ska punk band from Berkeley, California. Although only active between 1987 to 1989, their influence on the Bay Area punk scene and its subsequent main-stream success was huge. Two of the members went on to form Rancid, which was part of the mid-90’s revival of punk rock. Additionally, bands such as Green Day cite Operation Ivy as a major influence, and still play a cover of “Knowledge” live regularly.