Those pics were from January's race, called the Kilauea Crusher.
These races are part of the AMRA ( http://www.amraracing.com/
)race series. It's very simple and easy to partake in. In fact, your 1995 CR250 would be a very good bike. I was riding a 1994 CR250 prior to my 2001 CR500. Both were solid race bikes.
There are several levels of riders, divided into classes ranging from: A (expert), B (amatuer), C (beginner), and sportsman. Within each class, there are categories for displacement, age, or gender.
I race in the 250cc/450cc B class. There are 2 races, one for the A and B riders, and one for the C and Sportsman classes. Generally there's 100+ riders per race. Most riders start with Sportsman and work their way up.
The races are held on somewhat technical singletrack terrain and last for 2 hours (C/Sportsman) or 3 hours (A/B). Due to the slower, more technical race format... injuries are less common than in motocross. You're biggest enemy will be your stamina/energy.
You'll need protective gear and accessories for your bike (skidplate, handguards)... You'll also need a spark arrestor and hydration pack.
There are several clubs that belong to AMRA and each club hosts one or two races per year. I'm a member of "RockStars MC". http://www.rockstarsmc.com/httpdocs/index.php
We have our monthly meeting this Thursday, and were hosting the next race. It'll be a good meeting if you wanna attend. Meeting info scrolls across the webpage.
It's really a hoot. There's always a bunch of photographers out there taking pictures, so you feel like a real pro. There's also giveaways and trophys. I got trophys in my first three races.
Here's some pictures of me from last weeks AMA National in Mammoth (AMRA was chosen to host this one by the AMA). I'm not special, everyone who races gets glory shots.... I gotta admit it is cool though, especially when you become friends with the hundreds of people that race in these events.
I'm sitting down in a lot of those pics because my bike had a flat front tire and I couldn't push it hard.