Learn English – n idiom for making the same mistake repeatedly

A Russian acquaintance of mine asked me whether there's an English equivalent of "They keep treading on the same rake": someone walking or running across the backyard or garden steps on the bow rake's teeth, making the handle swing rapidly upward and whack the blunderer in the face: a comic device used frequently in old cartoons (such as Tom and Jerry) or slapstick comedy.

Now, this only happens once or twice in a cartoon, and can be written off as an accident. That's not what the idiom is about; rather, it describes the behavior … uh … modus operandi, if you will … of someone (or maybe a bunch of people) foolish enough to keep treading on the same rake (sitting in the same spot) over and over again. Or delusional, perhaps – you'll recall that Einstein once described crazy behavior as "doing the same thing in the exact same way while expecting different results."

Thus the idiom seems to apply to –

• bankers (or banks, for that matter) who scheme, swindle and cheat, and get burned, yet resume their murky activities once the dust has settled

• politicians (or political parties, for that matter) making an attempt, again, to make a system of ideas work that has failed many times in the past

• people arguing with their spouses of many years even though neither party can recall a single instance of their fighting yielding even remotely satisfactory results in the past

• folks purchasing $100 worth of lottery tickets every week for years on end

Etc, etc.

There's a bunch of English idioms that come pretty close ("fool's errand," "a fool repeats his folly," and something about stepping into something twice, etc, etc). None of them captures the humorous aspect of the behavior described above.

Here's a variation on the same theme:

Any suggestions?