I need new rollers. The ones I have give a ride like a washboard road and spit the drive belt off every five or ten minutes. They don't owe me a thing, since I got them free about 20 years ago.
Can't afford the sexy Kreitlers. Don't need or want a resistance device. I can get plenty of resistance from real life. The rollers are for smoothness and saddle time.
Once you master the basic balance and round pedal stroke needed to stay up unsupported on rollers you can begin to play games. See how fast you can spin before you self-destruct. Try some ultra-spin intervals.
One website says "your bike can list and veer just like it does on the road." That's pretty funny. It's much more abrupt and deadly than on the road. You can twitch the bike right out from under yourself in an instant. But after a while you will be able to sit up, ride no hands, maybe even scratch where it itches without slicing sideways into the nerarest piece of furniture. Then you will be tempted to try slow riding.
This really works best with a fixed gear, because you can change speed in mid pedal stroke without your brakes. The wheels respond instantly, and it's the wheels that keep you up. So slow down. Slow down more. See if you can actually come to a complete stop. Then go! You can't do a track stand on rollers.
One friend told me he knew someone who could ride backwards on the rollers. I don't know if he meant pedaling a fixed gear backwards, or putting the bike on the rollers with the rear wheel where the front goes and vice-versa, or actually sitting on the handlebars, facing the rear of the machine. Any of these would be impressive. All seem fairly pointless, so I've never been inclined to try.
Bobby Phillips, a racer out of Baltimore, could supposedly ride up to the rollers, bunny-hop onto them, ride for a while, bunny hop off and ride away. Bobby was wonderfully smooth out on the real road (and still is, as far as I know), so I don't doubt it. That's more flash than most of us need, but feel free to take any of this as far as you like.