Encino man was very good, but I'm not so sure it is appropriate for 8 and under. My brothers started running around willy-nilly saying the bad words. It was NOT helpful at the grocery store.
I like this movie, but if it came out today it would definately be rated PG-13. It contains many references to sex (no scenes though), underaged drinking, homophobic slurs, and more swearing than a typical PG movie.