How I Met Your Mother: "Symphony of Illumintation"

Quick Review: When it's not blowing your mind, it's pulling the rug out from under you. 

Episode Synopsis: Robin hears bad news, but hides it from everyone; and Marshall hangs Christmas decorations with a little help from his neighbor. -tvguide

Spoilers ahead, so watch the episode before you proceed. Seriously, there are some big things happening, so make sure you've seen the episode. Trust me.