I think in the US it's typically more like 22 minutes.

True, except during prime time, when they show fewer higher-paid commercials. They tend to run at about 25 minutes, though it varies a little more than the 22 minutes for everything else, which is fairly rigid.

In an incredibly annoying practice, NBC (at least) has taken to running ``super-size'' episodes of popular sitcoms during sweeps. They're usually 45-minute blocks instead of the regular 30-minute ones. This is so that they can elide their lesser performing programs while at the same time avoiding reruns. They sell it to the viewers as being ``15 more minutes of {Friends|Will and Grace|whatever}''. In reality, the episode itself is only slightly longer, with more commercials taking up 90% of the slack. Nice, huh?