I've always loved how we make it obvious that sites relevant to the interest of gay guys write boyz with a Z. Anyway, the tube in question today is called Boyz Tube and it offers you free access to a few adult videos that feature hot gay studs having hot gay sex. Simple idea and it has a fairly good execution too.
On the positive side, BoyzTube.com features around 300,000 videos for you to enjoy. It also has advanced filtering so you can toggle HD clips and sort by date added, scenes that have been awarded and those with the most views, comments and favorites. It also has categories so if you're down for seeing bears, Latinos, daddies or huge dicks you can do that with ease. Note that Boyz Tube has a bit of a community vibe too - it even has a forum (though it hasn't been posted in for quite a long time).
On the negative side, Boyz Tube is the only video streaming service that I've come across that has an auto playing video on the homepage. I don't like this at all, and I'd prefer sites stopped doing it. Additionally, you'll have to select 'thumbnail' view at the top of the results pages if you want a simple way to navigate through the content.