Hit F12 and no Dashboard appeared. Had to run Dashboard.app manually to get it to exist, and then F12 worked again. Added it to my Login Items, dunno if that's needed but shouldn't hurt.
The total neglect of this incredibly useful widget screen is baffling to me. I have weather, Deliveries tracking, stocks, Organized calendar/appointments list, PCalc, and iStat on a single screen. Used to have a nice meditation/tea timer, but it got broken a couple OS updates ago.