Vaguely parallel to preposition doubling, there's a phenomenon involving extra instances of that. A typical pattern is …VERB that ADVERB that SENTENCE, e.g. this comment by Robert Gibbs about Mary Robinson:
There are statements that obviously that she has made that the president doesn't agree with, and that's probably true for a number of the people that the president is recognizing for their lifetime contributions.
In this case, the adverb probably belongs earlier in the sentence ("There are obviously statements that she has made…"), and having stuck it in too late, Gibbs may just be using an extra that to fence it off from the rest of the subordinate clause.
But another possibility is to see the adverb as implicitly taking its own complement ("it's obvious that…"), kind of spliced in sideways. Here's an example from Anderson Cooper for which the adverbial-complement theory seems more likely:
So he wins round one, but he didn't get the bipartisan support that clearly that he wanted.
There's not always such a simple relationship between the adverbial and a corresponding tensed matrix (obviously ~ it's obvious that; clearly ~ it's clear that). Thus this re-complementizered sentence from a Beginner's Guide to AutoCad:
Shall the project managers have access to the files knowing that in most cases that they will mess up the drawings?
You could substitute "…it's true in most cases that…", or something, but there's no simple lexically-related complement-taking alternative to "in most cases".
In other examples, the adverbial itself can also be seen as a construction that might take a complement, as in this discussion of skinny-leg jeans:
I have unflattering thighs and thought that no way that I can fit in one… till the salesperson convinced me to just give it a try… and I did.
No way (that) is often used as a short form of There's no way (that), though it can also be equivalent to in no way, as in "I can no way afford that", or Anne Bradstreet's famous line "Thy love is such I can no way repay".
I do believe that all ho's can't fuck with me and it seems that apparently that they just wanna be me …
But I'm less clear about this example:
Do you ever get that feeling, though, that right when the proctor says "ok, pencils down and stop typing" that you missed something?
That one is from the latest blog post ("Death to Dead Law", 12/9/2009) by Sharon Eliza Nichols, the author of I Judge You When You Use Poor Grammar, and the creator of the Facebook group by the same name, which currently has 415,529 members.
As usual, the group's definition of "poor grammar" seems mostly to involve typographical errors, misspellings, and misuse of apostrophes, but there are also the expected peeves about vernacular morphology, clause-final prepositions, stigmatized word senses, and so on.
I'm not sure whether Ms. Nichols' sentence involves bad grammar (that is, a compositional mistake), or new grammar (that is, a emergent construction like Isis), or what. But whatever is going on, it's apparently not the kind of thing that her group or her book is involved in analyzing, much less judging. And anyhow, in the company of Robert Gibbs, Anderson Cooper, and Lareece, she shouldn't worry too much about being judged.