Wear them at E3 with a nice linen shirt and this sort of silly grey sport jacket made from thick sweatshirt material that I got from a Macy's in downtown L.A. and it all worked. I looked nice, but casual nice.
Oh, nearly forgot: You won't ever be tucking in shirts with these pants, because they're drawstring at top. And at bottom for that matter.
Very, very comfortable pants, these are. And great for button downs or t-shirts or polos. They've become my toss-on-and-go pants for the last two weeks—and the only pants I don't immediately change out of when I get home.
I'm taking a vacation next week to ride my new motorcycle up to Nova Scotia. (If the Canadians let me in. I still haven't gotten all my paperwork printed out.) It's definitely summer in New England now, so I'll be riding in shorts underneath full-length mesh armor when it's hot. But the pants I'm packing for that funky temperature between "hot" and "not so cold I want to zip in my armor's thermal liner" I'll be bringing along the Couch Commandos. They're comfortable enough I'm kind of hoping there's going to be a bit of a chill.

