from 1955 to 1980. Krewes Many of the events of Tampa's Gasparilla season are organized by "krewes", which are social and charitable organizations modeled on the krewes that participate in the Mardi Gras festivities of New Orleans. "Ye Mystic Krewe of Gasparilla" (YMKG) came together informally to stage the first pirate "invasion" in 1904 and has evolved into a registered non-profit organization which has organized the Gasparilla Parade ever since. As the planning has become more complicated over the years, however, the parade has accepted corporate sponsorships to defray costs and hired EventFest to coordinate the event with the city. Besides planning Gasparilla and its own private events, YMKG raises money for various charitable causes and annually endows several college scholarships through its community fund. The Krewe of Gasparilla was Tampa's only Gasparilla krewe until the woman-only Krewe of Venus was organized in 1966, the Ybor City-based Krewe of the Knights of Sant'Yago was organized in 1972, the Tampa Rough Riders were organized in 1978, and many more were established after YMKG opened up participation in the parade to more krewes in the 1990s. Krewes are centered around various ethnic, cultural, and historical themes or favorite charity causes, and much like the krewes of Mardi Gras, members often spend a great deal of money on elaborate costumes, beads, and floats. Currently, over fifty krewes march in the Gasparilla Parade of Pirates, with smaller krewes participating on a rotating basis due to the limited number of available slots. Many of the same krewes - large and small - also participate in the Gasparilla Children's Parade and the Sant'Yago Knight Parade. Throws Parade participants on floats and on foot have traditionally tossed souvenirs as they make their way along the route, but the specific items have changed over time. Plastic beads like those at New Orleans Mardi Gras festivities are by far the most prevalent item, with varieties ranging from simple single-color necklaces to intricate and expensive designs, most of which are purchased by krewe members themselves. So many beads are thrown that in recent years, the city has organized post-parade volunteer cleanup efforts which annually collect thousands of pounds of plastic from the parade route and nearby Tampa Bay. Though very popular now, beads were rarely seen at Gasparilla Parades before the 1990s. The two most common throws before that were plastic or metal commemorative coins produced annually by various krewes