How your brain takes out the trash while you sleep. The English man who crossed the Alps on a space hopper. And a subreddit where over half a million people pretend our world is just one big MMORPG. Sponsors:BitTrust IRA, Waive your signup fee BitTrustIRA.com/kottkeSkillshare, get a free trial of Premium Membership at skillshare.com/kottke Links:Deep sleep drives brain fluid oscillations (Science) During deep sleep, the brain does housekeeping (Reuters)Brain pumps comment (Christopher Mims, Twitter)Experience: I crossed the Alps on a space hopper (The Guardian)The Extraordinary Steven Payne  Documentary Official Trailer (Regijus Simkevicius, YouTube)What if life were a video game? These 650,000 people imagine it that way. (Washington Post)Outside: The free-to-play MMO, on reddit (r/Outside, Reddit)Kottke.OrgJackson Bird on TwitterSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.