State law compels you to join the Seattle Gin Society to attend the first annual Ginvitational, but it could be worse: Membership includes more gin events, gin tastings, and gin, gin, GIN. The Ginvitational itself includes 15 kinds of gin, with local distillers Batch 206, Captive Spirits, Oola, Sound Spirits, and Sun Liquor represented. Start with the top five, as selected by judges such as Murray Stenson of Canon and Anu Apte of Rob Roy; continue until your taste buds give out. The Society’s favorite will be crowned the best gin in all the land, and you will stroll ginnily through the park. (Shelter House at Cal Anderson Park, 1635 11th Ave, www.gin-society.com, 2–7 pm, $25 adv/$35 door, 21+)