too late to challenge a moving violation ticket if it's been paid?

Probably a long shot, but a friend of mine got a ticket, forgot about court date, was out of town when date was coming up, so he paid it with their online payment system. I guess that's technically pleading guilty. And it's spilled milk, but if one was so inclined (or hell-bent) on trying to challenge the ticket, is it possible? An appeal perhaps? Is there a technical word/procedure for this?

Yes, paying a fine online for a ticket is pleading guilty. My advice would be to tell your friend to call the court and ask the next time it will be in session. Then he should go ask the judge to change his plea from 'guilty' to 'no contest' and ask for deferred adjudication. The judge has the power to do that (as long as the request is timely made). If the judge grants a deferred, and your friend does everything he's required to do, the offense won't appear on your friend's driving record.

I think it's done with. For the future though, the way I handle tickets is to just fax them to my lawyer the day I get them. I've had all of my tickets dismissed in the last 7 years and being that I like fast cars I used to get a lot of tickets. I have the lowest insurance premiums, full discounts, based on having no accidents and no ticket convictions. I haven't had any tickets in the last 2 years though, because I run a good radar detector (Valentine 1) and use laser jammers (Laser Interceptor brand) on my cars. It's not fool proof, but it helps a lot .

I thought laser jammers (link) were illegal in Texas . . . I have better luck beating laser by driving with my brights on during the day when my V1 (great damn product, BTW) squawks.

I thought laser jammers were illegal in Texas . . . Originally Posted by Jackie Devlin

So is speeding .. and hobbying. It's not a big deal if you're caught, better risk it than get laser tickets. Plus I always jam, slow down, then turn off the jammer so the cop can get a speed reading. Though sometimes there isn't enough distance at the speed to turn it off, in which case you do see the cop go "WTF?" and stare at his lidar gun in confusion.

CLASS C MISDEMEANOR. An individual adjudged guilty of a Class C misdemeanor shall be punished by a fine not to exceed $500.

Not particularly concerned.