Have you tried Free Studio? I haven't tried it but meant to and forgot about it when I needed it. I've heard good things about it. Might try that and use Audacity for what that doesn't do.
FS is Free Studio.
Violet triangle is my dongle dialler, Ucell Internet. An alternative to my main Reliance dialler from some foreign company. (They built that dialler for ZTE modems.)
I use DVDVideoSoft Free Studio: http://www.dvdvideosoft.com/free-dvd-video-software.htm#.VM9SEy5LVpk
It has a YouTube video downloader and some other useful utilities. If you are only interested in the video downloader, you can download it separately.
DVDVideoSoft Free Studio. Includes a YouTube downloader that can save in lots of formats and qualities. It includes HEAPS of other stuff video, image, and music related. Its all free.
Dvdvideosoft's Free Studio, there's just a shit load of stuff in it and it all works perfectly, I've been using it for 6 years now and I've never had any problems, no viruses or anything.
As /u/looking4artist mentioned, if you want it to play on a traditional DVD player it needs to encoded correctly.
This is a bundle software that will let you do final conversions from mpg4 to other file formats and then also let you use another tool to burn the DVD. Just be aware it has a bunch of bloatware and other junk it tries to install on your computer as well, so be very careful when reading installation instructions to not let it install extra junk.
I'm not a huge fan because of all the bloatware, but it essentially has all the tools you would need to do any conversions or burning.
http://www.dvdvideosoft.com/free-dvd-video-software.htm
This software lets you download youtube videos as mp4s and save them on your computer so you don't have to have an internet connection to watch them. I've used it before, really straightforward and helpful. I actually used it to dl some French and Italian language videos. So maybe learning a foreign language would be another option for things you could do.
I just started a new job working third shift so I have a ton of downtime too. I'm loving this topic, lots of good ideas.