I remember first watching John Guare's play Six Degrees Of Separation (now a film with Stockard Channing and Sidney Poitier) and discovering the the ory behind the title. If you do not know it, let me explain. The idea, as I understand, is that each person on Earth is separated from every other human by only six people. In other words, I don't know Madonna, but, in fact, she is removed from me by only one degree because a former colleague, a music writer, does know her. Let's take as an extreme example a bushman in deepest Africa. Well, I have a friend who has a friend who works for a relief organisation. That friend knows someone working on a project in Africa in the very village where our bushman lives and she knows him well - just three degrees of separation. The theory is that it takes only six moves before we are all connected. What I am leading to is how careful you have to be in this world - you never know who knows whom. Here am I writing away, ranting about this, slagging off that, not realising how few degrees separate me from the people behind Tekwar (World, 8.30 pm). Not William Shatner, of course (though I do know a Trekkie who no doubt knows someone who cleans Shatner's shoes everyday), but one of the bit actors. I discover only latterly that my boss' sister-in-law is a Canadian actress who was shot to pieces in the first episode. I may have called it 'the worst sci-fi series ever to grace our screen' but, in retrospect, I reckon it was because she didn't make it to the second episode. There was a depth in the acting in the pilot that has been missing ever since. I also realise, now, why I have never been much inclined to enjoy the RoboCop series - the man in the suit lacks a certain presence. And, can you believe, I am separated from him by only two degrees. The same boss' actor brother-in-law was due to play the part but lost it when it was decided his thighs were too big. Such are the vagaries of Hollywood. Anyway, to be charitable, I give Tekwar a mention this week - just in case a friend of a friend has a bit part this week and it's their big break. In tonight's episode, Sam's first day at the Cosmos Agency may be her last when she is assigned to infiltrate a powerful mafia-style family. I only hope there are at least six degrees separating me and Mr Blond (aka Michael Madsen), the thug whose shoe-shuffling rhythm brought uncompromising menace to the torture scene in Reservoir Dogs. Since then, Madsen has earned himself quite a reputation and quite a few parts as a psycho. Yet the handsome actor, who has been around for a good few years, is equally reliable as the good guy. In Final Combination (Pearl, 9.30 pm), he plays an LA cop whose wife has gone the way of most LA cop's wives. His love life looks unlikely to turn up anything apart from one-night stands, until, that is, the beautiful Lisa Bonet comes along. Naturally, she is not there just to add charm to the film; she is connected by just one degree to a serial killer. Tonight's Global Family (World, 6.30 pm), The Song Of The 17-Year Cicada, really is worth a watch. Once every 17 years in some areas of North America, there is a mass emergence of the 17-year periodic cicada. This film was recorded in a Chicago suburb in May 1990. After almost two decades underground, the 17-year cicada spends barely three weeks above ground - just long enough to breed and lay its eggs. Then it dies, leaving behind a new generation - and thousands of damaged trees and shrubs.