possibly the greatest animated series ever, was on ch4 a while ago until it got buggered around the schedule. It got canceled after the 3rd season in the states cos the tv execs were asshat. It then went to to become the biggest selling tv series on DVD ever. It came back for a forth season recently in the states and has spawned a direct to dvd movie as well.
You can download series 4 episodes off one of your favorite P2P systems if you wish, although i would heartily recomend picking up the DVDs, season 2's probably my fave.
http://www.familyguy.com/
PS. As a side point, I've been hearing that BBC3 has now got the rights to Family Guy and will be showing Season4 soonish.