The Kumars at No 42 BBC1, 9.30pm If it's Friday night it must be chat show night. And now that Jonathan Ross is taking a break from asking prospective prime ministers embarrassing personal questions, the Kumars, aka Sanjeev Bhaskar et al, step into the breach and invite talk-show host Trisha Goddard and X Factor judge Louis Walsh to chew the fat round their house (by which we mean their TV studio). I don't know . . . Louis Walsh. Would you invite him into your home? No, me neither. Rearrange the following words - bottom, scrape and barrel - and you'll have the measure of this. A shame, really.

Transmission Channel 4, 11.40pm Alas, this is nothing to do with the Joy Division track of the same name, but the latest televisual attempt to put pop music on the small screen. On tonight's show are Boy Kill Boy, Primal Scream, who can also be found striking the same silly rock poses on BBC2 round about now in the latest highlights from T in the Park, and last - and by all means least - the ridiculously-fullof-themselves-for-noapparent-reason Razorlight, howling their hearts out. Presenter Lauren Laverne, one-time frontwoman of indie chicks Kenickie and smarter, more sussed and more talented than anyone on stage, looks on. There's something wrong with the way the world is set up, really there is.

Athletics BBC2, 6pm Another long night in this long summer of sport, as Hazel Irvine presents live coverage of the London Grand Prix from Crystal Palace. Joint world-record holder Asafa Powell is the main attraction in the men's 100m. The Jamaican had hoped to race against rival Justin Gatlin, but the American was forced to pull out of the event because of a leg injury, leaving Powell as clear favourite to triumph in tonight's race.