RE: log on vs. log in,
I couldn't begin to say why, but I tend to think of logging on as establishing an actual network or internet connection, e.g. dialup, or, as was mentioned in the old days, connecting to a time-shared mainframe with dumb terminals. If your not logged on, your terminal is a paperweight. You're not ON the network or ON the system at all. I think of logging IN as providing a username and password to get access to a particular area; a website, a shopping cart, some secure locality, etc. You can be ON, but not IN.
I won't swear to it, but I think you'll find this to be often true in common usage.

Voltaire, are you implying that a colon cannot be used to join what would normally be two sentences? I vaguely recall such a joining as correct and proper as long as the colon is demonstrating some relationship between the sentences, but that semicolons should not be used to join two complete sentences.

I would agree with much of what was said below, except that I think that Speedwell's metaphor is too narrow. It is used to describe any attempt or planned attempt at something that is clearly unattainable, dubious, or just plain crazy.

I thought you'd all find this interesting. I saw a little dig against Microsoft below, but the truth is that when using Microsoft Word, you can set the grammar checker to use either one or two spaces after the period. The default is one, but you can change it to two.
I'm not sure I agree with what some of you said about variable pitch fonts used in computer word processors. Your logic is flawed. Usually, when a word processor changes the spacing between words, it makes the single space smaller than a letter, not larger. This would make double-spacing after a period more important, not less.
Personally, I double-space after periods most of the time, except in some informal e-mails and quick typed notes where it is simply a matter of saving time or space.

You can also use an ellipsis to signify the passage of time, or a delay. The ellipsis was discussed at length on this previous posting:
http://www.painintheenglish.com/post.asp?id=482

Ok, now I can use three "that"s:
"Now that I consider that, that that is important suddenly becomes obvious."
Maybe not the best sentence, but it works.

I agree but would like to be more specific.
"assists in" is followed by a verb.
"assists with" is followed by a noun.
It just so happens that drafting can be a verb or a noun, so both sentences make sense if only slightly different in meaning.

I would agree with Matt. The "now", resolves a potential ambiguity. Compare it to "Three months after his father’s death, Dave was still running the shop."

I noticed that everyone's examples are relying not on the grammatical use of "that" as a part of speech, but simply as a word. If I say, "where should I place that "that" in the sentence?", clearly the second "that" could be any word, and really isn't a proper use of the word "that". Yes, I know, the sentence is grammatically correct, but I could propose this sentence:

"I saw the word "that" written one hundred thousand times in a row, appearing as: that, that, that, that .... that"

There. I just used the word "that" one hundred thousand times in a row in a grammatically correct sentence. I could make it a million or a billion or arbitrarily large. I've solved the problem, but not very creatively or elegantly.

How about a more interesting approach? How many times can you use "that" in a sentence, where the word "that" is actually and properly functioning as the word "that" and NOT just as some arbitrary noun?

I can do up to two "that"s in a row:

"I am very disappointed that that is the best excuse you can come up with."

Can anyone get three? more?

Or, also may be from archery; missed the bullseye is off the mark.