I've put the odds 'n ends of my portfolio here.
As you can see, it's a small hodge podge of one-off articles, adverts, and other miscellany.
I'm always tickled pink when a non-gaming publication contacts me, whether they're contacting me for the purpose of writing a piece or just to pick my brain.
Writing ad copy is an interesting process, not unlike that of preparing a preview. The big difference is that you have to be peppier and pithy.
Be brief and catch their attention -- that's the key.
Also, unlike editorial writing, a typical advertisement will go through at least 10 revisions before the client signs off on it. The editors and marketing people want the ad to be "just right," and they'll nitpick until it is.