Gaming What do you wear as a top when you perform (barrel race, pole bending, etc.)?
Normally either a tank top or t-shirt -- I overheat *extremely* easily, so short sleeves are a must. Recently though, I've taken to wearing a short-waisted corset as well -- it helps my posture and, as I'm quite 'top-heavy', is phenomenal for support.
What do you wear on your legs? Do you ride in a certain brand or style of jean? Or do you wear darkers colored jodspurs when you game? Some people choose to wear chaps. Do you?
Just jeans. Nothing special about them, so long as they fit. I do have a pair of chaps, but -- because of the above-mentioned overheating -- they don't get much use.
What do you wear for socks and boots? Do you wear normal everyday socks or riding socks like zocks and ovation? Do you wear cowboy boots, riding boots, or paddock boots? If so, what brand?
Any socks, so long as they are knee- or thigh-highs. Best as I've been able to tell, Ovation/Zocks/etc aren't really any better or worse than the cheapo Wal-Mart brands.

Just more expensive and prettier.
For boots, cowboy boots 24/7! My current pair are Ariat's, but I'm not really brand-loyal.
When you game do you wear a helmet or a cowboy hat? If so, what brand do you wear?
Neither. I've had some bad experiences with helmets (yes, they were properly adjusted/fitted/etc), and I used to have a cowboy hat (forgot the brand), but it got *destroyed* and I've never gotten around to replacing it.
I have an old straw hat, but it falls off everytime I run, so I don't bother wearing it.