TV blooper shows are usually about an hour long, and consist of lots of mistakes from other TV shows, unless the show's makers are feeling particularly bored, in which case you may find some bloopers from other blooper shows thrown in.
Blooper shows are always shown on Saturday evenings, after you've had your tea, a time when you might decide that instead of doing the washing up, you'd like to be entertained. It's a little-known fact that these shows were devised by angry wives and husbands who wanted their spouses to stop lazing around watching TV of a Saturday evening, enjoying themselves, and instead clean the dishes like they ought to be doing.
The two main bloopers shows in the UK are run by the BBC and ITV: Auntie's Sporting/Natural/TV/Whatever Bloomers, hosted by Terry Wogan, and It'll be Alright on the Night, hosted by Dennis Norden. Whatever possessed TV executives to broadcast such utter tripe is beyond understanding. If the general public wanted to watch hours and hours of great televisual mistakes, then they'd watch cable TV.