Feedback from someone who's not going *hides*
Just by reading the text, I instantly get the joke, a clever one at that. Hence it might not be necessary to put additional images conveying ponies or rides. I think you run the risk of spoiling the theme's effect by putting such images.
Instead, you could have "Free PWNY Rides" and put something cool, hardcore, like a mean-looking CT with a smirk on his face who's looking right at you with his M4 taking aim,
(basically a CG image instead of a real-life pic)
that places more emphasis on getting pwned. As Bewildered pointed out, the notion of "come play with us and get pwned" needs to be conveyed.
Or if a lighter tone is what you want, then maybe something like
(not the most suitable of images, but you get the idea)
Or something cute
(meet mo, sniping from his NYC apartment )
Also, kudos to Bandit and everyone who's working on this. Bringing a theme to life is never easy. Tried it once myself.
Just my 2c's worth