Water slides are like active volcanoes—both melt away T-shirts, propel fluids down super-steep slopes, and have a lot of screaming nubile women thrown down them. Leisurely lounge or ride the tidal-waved slides with today's Groupon at North Clackamas Aquatic Park in Milwaukie. Choose between the following options:

• For $10, you get a family admission (two adults and up to four children) to Big Surf! and four individual rock climbs on Steel Mountain (up to a $36 value).
• For $5, you get one admission to Big Surf!, one rock climb on Steel Mountain, and a locker (up to a $13.99 value).

North Clackamas Aquatic Park's indoor hydro-haven breaks albino winter skin from its sweater prison, brightening the chilly Northwest solstice with unhinged summertime fun. The aquatic playground of Big Surf! launches swimmers into a tubular twist of water slides and a maritime maze of swimming sanctuaries, including a six-lane competition lap pool, hot tub (ages 18+), 13-foot deep-diving well, and wave pool. Altitudinal landlubbers, meanwhile, can scale the rough-and-tumble terrain of Steel Mountain—a 29-foot rock wall with three routes of varying vertical difficulty—and build the necessary upper-body strength for tree climbing and thievery of pterodactyl eggs.

Reviews

Today Travel placed North Clackamas Aquatic Park in its top-five family-friendly water parks. Five Yelpers and seven Insider Pagers give the water park a four-star average:

• My girls LOVE this place and my youngest thinks she's the bravest girl in the world for going down the big slides. – Denise E., Insider Pages
• This place is pretty much a water wonderland, especially if you have kids. – Danielle K., Yelp