Front-country geysers are spectacular, but there’s something extra-special about a backcountry spouter you have all to yourself (or more likely, to yourself and a few other hikers). Lone Star Geyser is one of the easiest ones to reach, and it’s predictable enough (eruptions happen every 3 hr. or so) to make catching its show likely: The 12-foot-high cone sprays water 45 feet in the air. Getting there means tracing the Firehole River on an old service road, passing intermittent meadows along the way; bikes can follow it almost all the way to the geyser. Check the register near the geyser to estimate the next eruption time.