The Mauna Kea Visitor Information Station atop the 9,300-foot perch of Hawaii's tallest mountain, Mauna Kea, hosts a nightly stargazing program featuring a cosmic tour of the universe -- with an astronomer pointing out stars and constellations with a green laser beam. Don't miss the 13,796-foot summit: It's home to 13 of the world's largest telescopes. Bonus: The show is free!
Grab a Bite: On the drive up to Mauna Kea, detour to nearby Waimea to try the regional cuisine of Merriman's, which gets much of its produce and seafood from local sources. The spicy fish taco with guacamole and charred tomato salsa are a must ($13).