Four aliens come to earth in earth bodies to study people. They are a family; Commander Dick Solomon (John Lithgow) is the father to Tommy (Joseph Gordon-Levitt), the teenage son, who is also the research officer and the oldest alien on the mission. His aunt, the stunning, gorgeous Sally (Kristen Johnston), is the head of security and then there is Harry (French Stewart), who is essentially the radio. They answer to The Big Giant Head, an entity back on the home planet (played for a few episodes in one of the later series by William Shatner). Over the course of six seasons, Dick falls in and out of love with Mary (Jane Curtain) a professor of anthropology at the second-rate university where he lectures in physics. Sally falls in love with Don (Wayne Knight), a pudgy, cowardly cop.
Lots of stuff happens over the seasons, there are fabulous guest stars (including John Cleese, Laurie Metcalf and Christine Baranski) and the characters develop and change beautifully.
I’ve watched this series many, many times. There is fabulous slapstick and brilliantly over-the-top performances throughout. It’s been wonderful to see Joseph Gordon-Levitt go on to a stunning film career; watching him as a teenager holding his own with this awesome cast shows what a strong performer he is. John Lithgow continues to appear and delight me in many things, from 30 Rock to Dexter.