Hay limpster,
I have the same thing at my school but I have learned that it is best all around if you just ignore it, and if you have a question about a sites contence ask your system administrator to review it for you....
I do agree that filtering is wrong but since the CIPA act was introduced it is illegal for any public school receiving federal funding to have open internet access..... They can also get fined if the feds find that a student found a way to get past the blocking system....

I know that it is really annoying, the other day I was googleing some things about driver’s education and it blocked a site saying that it contains porn..... But you know what I did... I pressed the back button and kept right on looking....

I have learned that if your are looking for legit info (no porn, no illegal stuff) you can always find it on a site that is not blocked...

I hope this helps....