Father's Day is a weird one for Solver. He has stories of his dad, but not a lot else, but he still feels cause to honor him. As it is, Solver is a constant crusader for changing the world for the better. He barely needs sleep, has no secret identity and never really has, has very little in the way of hobbies - unless one considers adventuring and crimefighting a hobby, and typically insists on stopping at least one crime, averting one disaster, or otherwise changing the world for the better, even a little, every day before breakfast, or taking any kind of break.
Father's Day he always goes all out - the entire day is dedicated to rescues, city and disaster patrol, and anything else that arises, figuring that, somewhere, his dad would approve.