I just finished this anime earlier today, and I must say it is one of the best anime series I have seen in a long while... Which is a shame, really, because almost nobody has heard of it. The series is about a group of students (teenagers) training to be astronauts a few hundred years in the future (2225, I believe). While on the training center in space, the entire thing gets sabotaged, eventually leaving all of the adults dead and the children in a rapidly desintegrating ship. With no other choice, they have to turn to a mysterious ship called the Ryvius, which was hovering above them. Once on board, they realize that nobody is there and decide to stay there until help arrives... But help doesn't appear to be coming. They are forced to try and create a functioning society while waiting, and as time wears on, the situation rapidly deteriorates. It's often compared to the famous novel The Lord of the Flies by William Golding for this reason. In fact, I'd say most people consider it the Lord of the Flies of anime or science fiction. Needless to say if you liked Lord of the Flies (Most people apparently don't, but I loved it), you're going to like Infinite Ryvius as well. I still think, though, that if you didn't enjoy that novel that you'll still like Infinite Ryvius, as it's presented in a more approachable manner. I found it to be pretty deep and thought-provoking, especially towards the end, when things begin to get much more tense -- I'd even say it's one of my favorite anime of all time now. I highly recommend this show. It's a bit old now (1999), and I must warn that the first six episodes or so were so confusing that I tried watching the show twice before I finally got through them, but it's definitely worth watching.
I actually bought a collector box a long time ago of that series. Had the vol. 1 DVD, 4 pencil boards, and a plush ferret in it. Haven't exactly had a chance to watch it yet. But if you say it's good, I shall.
I liked it! :D It wasn't wonderful, but it was pretty good. I wish that more people would know about it though...it's a shame...