The May 6 District of Columbia gambling referendum proposes the legalization of: CITY-OPERATED NUMBERS AND PERIODIC LOTTERY GAMES -- A total of 60 per cent of the amount wagered would be returned to winners in prize money, a higher share than in any other U.S. lottery. Gambling proponents say $30 million could be raised annually from the games for three categories: Authorized, but unfunded D.C. government programs, special education instruction and private, nonprofit groups that provide groups that provide services for D.C. residents. COMMERCIALLY OPERATED JAI ALAI -- Parimutuel wagering on the fast-paced Spanish sport would be permitted, and gambling proponents say about $3.9 million in revenue could be raised for the city, special education and nonprofit groups by the third year of operation. Three firms have expressed an interest in operating a jai alai arena here. COMMERCIALLY OPERATED DOG RACING -- Parimutuel betting would be permitted at a greyhound racing track, and gambling proponents say that $2 million could be raised annually if racing were held 100 days a year. A Massachusetts firm has expressed preliminary interest in opening a track here. BINGO AND RAFFLES -- Charitable, religious, educational, civic, fraternal, other nonprofit groups and senior citizen organizations could conduct these games and drawings after receiving a city license. Periodic "Las Vegas Nights" and other events with games of chance could be hold by the same groups. The city would receive no money from this gambling, other than minimal license fees. SOCIAL BETTING -- Wagering among individuals, such as at private poker games, would be legal if the organizer reaps no profit. A FIVE-MEMBER DISTRICT OF COLUMBIA GAMING CONTROL BOARD would be created to set gambling regulations and oversee wagering operations in the city and the distribution of gambling revenue.