A serious season of That '70s Show? Perhaps that's a stretch in terms of describing the sixth season of the well-loved teen comedy series, but more than a few moments of gravitas slipped into the slapstick adventures of Eric Forman (Topher Grace) and his pals during its 2003-2004 network run. That's not to say that laughs weren't the order of the day; on the contrary, there are plenty of funny episodes throughout season six, thanks mainly to Kelso (Ashton Kutcher), who finds himself a new dad via new girl Brooke (guest star Shannon Elizabeth) and a police cadet (Jim Gaffigan appears as a fellow officer); and Fez (Wilmer Valderrama), who marries Eric's sister Laurie (played this season by Christine Moore) to avoid deportation. But there's the issue of Red's (Kurtwood Smith) overtaxed heart, and wife Kitty's (the always spot-on Debra Jo Rupp) feelings of neglect; Hyde (Danny Masterson) and the true identity of his father; and biggest of all, the romance of series sweethearts Eric and Donna (Laura Prepon), who decide to take their relationship to the next level by getting engaged. Season six is an enjoyable blend of low-key drama and broad laughs, well played by its likeable cast; guest stars this season include Brooke Shields, Seth Green, Rachel Bilson, and Alyson Hannigan, and Luke Wilson and Tanya Roberts make return engagements as Kelso's brother Casey and Donna's mom Midge, respectively. --Paul Gaita