( )s and , ,s and -- --s

Either:

He never played a videogame--they were silly, he thought--but was instantly amazed by its beauty the first time he did.

or

He never played a videogame (they were silly, he thought) but was instantly amazed by its beauty the first time he did.

or

He never played a videogame, thinking they were silly, but was instantly amazed by its beauty the first time he did.

I use dashes like Maestrowork. Seldom if ever use parenthesis. To me they seem old fashioned.

Gosh, you guys need an English professor, and I just happen to be riding by on my horse named Punchooayshun!

A parenthetical phrase is an aside to the reader. An aside is a sort of digression outside the main meaning or thrust of the sentence, or to add to the sentence. Whether you use parentheses, commas or em dashes (em dashes and en dashes in old type setting were the width of the letters "M" and "N" respectively), you are making an aside.

In fiction there are a few connotations to the use of each type of parenthetical phrase. Using parentheses is sometimes considered bad form in fiction because they were so often used as authorial intrusion a century ago. Some fiction teachers and writers say not to use parenthesis for this reason. Commas or em dashes are thus preferred, with commas making the phrase less emphatic and Em dashes more so--to the point of being "in your face".

You need something stronger than commas to set off "they were silly, he thought." That is, don't do this:

He never played a videogame, they were silly, he thought, but was instantly amazed by its beauty the first time he did.

Incidentally, the sentence should start "He had never played..." The time when he first played a video game came after the time when he never played one.

I suggest getting a grammar book and reviewing punctuation. It will answer most questions and explain why a comma is needed between "they were silly" and "he thought."

Comma

I agree with reph. You can't set off "they were silly, he thought" with commas. Parenthetical expressions should be set off with commas, but this is not a parenthetical expression. In fiction, such a phrase really doesn't belong in the sentence at all, but if it is there, commas are not strong enough to support it. "Had" does belong in the sentence, however, and the sentence really makes little sense without it.

I would say the problem here is more one of style, rather than grammar.

Parentheses are not old-fashioned, and when called for by the rules of grammar, need to be used. Commas, dashes, and parentheses all have specific uses, and the correct one should be used according to the rules. The problem, I think, is that too many writers do not know the rules.

The first five or six pages of "The Elements of Style" teach pretty much everything a writer needs to know about any of these issues.

Akuma, be sure to check out the Grammar for Grasshoppers forum here on AW.