Multisite or not?

Hello all. I am looking for advice on what path to take. I currently have my woodworking/DIY website http://www.jayscustomcreations.com and want to make a specific section dedicated to a new YouTube series I am about to start. I want this section to have a seperate wordpress theme though. It will be almost entirely YouTube videos so I am wanting this section to have a multimedia theme. Is it possible to install a second theme on my site? Something like mywebsitename.com/sketchuptutorials will take you to the second theme and clicking back to mywebsitename.com will show the main theme. Or do I need to go the multisite route and create a seperate domain for the multimedia theme? I hope this makes sense and if you can point me into the right direction for further research that would be great.