While not really rocketry, high altitude balloons do offer great access to altitudes above 50,000 feet, and can keep a payload up for many hours, which contrasts with the few min. of a rocket flight to the same level. One of the best uses of this is to take images at altitude.
These balloons work with lighter than air gasses, generally either hydrogen or helium. They are mostly simple latex balloons, which are sealed systems. As they gain altitude, they expand a great deal, often as much as a small house. Eventually, however, they burst and the flight ends. More high end flights can use open systems, where excess gas can leave the bottom of the balloon (like a hot air balloon). Anyway, check out the web page. Lots of more images and more detailed info about the hobby.
Montana Borealis Project