Sorry about your knee, I too have been out all season with a badly broken wrist so I feel your pain. Similarly, I also busted out my camera and got back into filming. Of course, it's not skiing footage I'm getting, more just videos of stuff my friends and I do like our weekend camping trip at the ocean etc.
From what it sounds like, you have a point and shoot camera? Those will do the job but it'd be good to step up to something that's actually meant to shoot video. Honestly I can't tell you what to film, but there is really no bad way to go about it. Making movies is a ton of fun however you do it. Making music videos with friends can be a good way to gain experience with your camera or do an MTV Cribs style video.
What you will want to get is a good editing program. iMovie / windows live movie maker will get it done, but they are very limited. I use Adobe premiere pro CS5.5 and I have very few complaints. Hope your foray into the video world goes well.