This one's for sushi lovers only (though, really, who doesn't love sushi?). At National Geographic Live's Grand Sushi Event, author Casson Trenor signs copies of his book Sustainable Sushi while local chef and National Geographic Fellow Barton Seaver offers a tasting of sustainably caught or farmed sushi with wine and sake pairings. Presented with the National Cherry Blossom Festival and co-sponsored by Genji Sushi. Wednesday, March 30, at 7 p.m. National Geographic Society's Gilbert H. Grosvenor Auditorium, 1600 M St. NW. Tickets are $100. Call 202-857-7700 or visit nglive.org.