Whilst the quite well known 'Our Relations' is the main feature on DVD 5 in the Complete box set, I actually think that much shorter 'Brats' has more of the pair's classic slapstick than the others and is funnier.
'Brats' has Ollie & Stan creating havoc around and on a pool table, whilst the brats in question are two little boys (impish Stan & Ollie again) with everything, including the furniture made much bigger to make them appear small. At one point an animated mouse appears to have been drawn onto the film's negatives, the creature being on Ollie's back whilst Laurel gets a gun to shoot it off. The tiny pair then take a massive bath that overflows, disastrously (of course) then they undertake a boxing match - Stan flailing about with huge boxing gloves will always looks funny. Adult Ollie then sings them a lullaby that goes on to sound more like an opera!
'Our Relations', in contrast, takes too long to get going and at over an hour long, it's only the last 10 mins that it gets genuinely funny. It's more the mix up of identities than the script that's amusing. The ending, though, is absolute classic, as the pair's feet are set in concrete and they fall about like Subbuteo footballers.
The last, Twice Two, has the pair dressed up as women and their voices are dubbed. Their normal, male counterparts have verbal matches too and then all four. These are quite good, but nothing special.