Edit (about a year later): watching these on repeats, I think they come closer to 3 stars than 2.5
Remember I said there a load of medieval kid's programmes around at the moment, and most of them are pretty good. This one of the pretty good ones. Not as funny as the two best ones, 'The Big Knights', or 'Sir Arthur and the Square Knights' (which is 40 years old, but nevermind), 'Arthur's Disasters' is still a likeable, well-written, and slightly surreal show that nearly gets 3 stars from me.
The animation is pretty basic, but that doesn't really matter. Basically each episode involves Arthur going off on some absurd quest which the ever aloof Guinevere has set him, in order to win her love. Merlin and Launcelot generally get dragged along (incidentally when a show's official website refers to one of the characters as 'narcissistic', it's probably a reasonable assumption that the show isn't just aimed at kids). In fact there is a python-esque edge to the humour (though again, maybe not so much as in the VERY silly 'Big Knights'.)
For some reason, I think one of the funniest things in the show is that Arthur's horse is called Alan.
This is a show which I enjoy quite a lot when it's on, though I don't organise my day around trying to catch it. Worth a watch.