That's my goal too. I've cracked airplay now, so music's sorted. Now need to figure out how to throw video directly from the Mac.
From the likes of YouTube? On your Mac there'll be a mirroring icon at the top right on the bar. You'll need the latest OS though & I think a new machine, as my MacBook Pro does it but the OH's Pro is an older machine & although it has Mavericks I don't think he's got it. If you've got Mavericks installed have a look. It looks like this, but only on a page etc which has video on it; Google homepage no, YouTube yes