It's hard to guess from the title which recent epic error they might be referencing:
I first considered Cash-for-Clunkers, which paid tax dollars to destroy wealth and thus create union jobs, a waste of $3 billion, which is comparatively small but still gets style points because the program was 100% wasteful, without even a pretense that the money would do any good for the country as a whole.
Next, I considered the shovel ready projects (oopsie, even Obama admits there were no shovel ready projects, but we still spent the money) funded by the $830 billion Stimulus Bill, which killed jobs but at least made many politically connected campaign donors happy.
How about TARP, a program to reward the Too-Big-To-Fail financial institutions with $700 billion in taxpayer dollars so that there would be no penalty for risky or irresponsible investing and those banks could get even bigger?
Or it could be nationalizing an inept and corrupt auto company to create Government Motors and take a giant step toward something on the spectrum between crony capitalism and national socialism, a work of criminal artistry for which it is difficult to calculate the cost because many private individuals paid the price of ignoring contract law, bankruptcy law, and all other relevant laws that used to govern business practices back when we believed in the rule of law.
Then there is ObamaCare, a massive extravaganza that would eventually dwarf the rest of today's federal budget, guaranteed to kill medical progress in America, kill our grandparents (our parents for those who are older, and us for those who are retired or approaching retirement), to wreck the federal budget, to reduce the quality of medical care to what we see at the Department of Motor Vehicles counters, and to hurt the re-election chances of the thugs who forced an unconstitutional law through Congress in opposition to the will of both the general public and constitutional scholars.
Frankly, it's hard to find anything the Congress has done since Pelosi's rise that has not been a blunder. The only reason they haven't made any budget blunders recently is that they no longer bother passing a budget. The GOP mostly varies from disappointing to disgusting, while the Democrat Party ranges from colossal stupidity to pure evil. Between the two sides, finding Congressional Blunders is like finding grains of sand at the beach or useless teachers at an urban school.