Experimental Rocketry involves very large rockets, usually with liquid fueled engines. The rockets used here are much larger than those used for High Powered Rocketry, and capable of extream altitudes. I believe that amatuers will soon be able to launch small objects of up to a couple of hundred pounds into earth orbit. When this happens, the first part of the "probes" section will be achievable completely by amateurs.
The Space Frontier Foundation annouced in November 1997 that they will award $250,000.00 to the first person or group not connected with a government entity to launch a 2 kilogram payload to 200 kilometers in altitude, and there are several people who are almost ready to try. The contest ends on November 30, 2000. See their web site for details.