Lake Crescent is also an incredibly cool place to SCUBA dive. The water is gin clear and you feel like you're diving in the Caribbean only you surface and realize you're still on the Olympia Peninsula!
Quick story: Back in the summer of '84 I heard about an old logging steam train that had rolled into the lake, so we went over to check it out. When we started talking to old-timers the story started to unwind; well it wasn't a train, exactly, it was a steam shovel on a flatbed car. Well, OK, the car didn't roll in, just the steam shovel fell off.
Down under the lake, at 155', right off the bend where there were still RR tracks, we found the truth: an old steam shovel bucket! Still a cool find and dive, though.