The Hopkinton Parent Teacher Organization (HPTO) is celebrating its 30th anniversary with a ’90s Prom Birthday Bash on Saturday, April 6, from 7:30-10:30 p.m. at the Hopkinton Center for the Arts. The event features a live ’90s cover band, silent auction, desserts, drinks and dancing. For more information and to purchase tickets, visit hptoonline.com.