In 2005, following a lengthy process initiated by EAA, the FAA sanctioning a special type of aircraft, designated "Light Sport" that would be lighter, and slower than conventional light aircraft.  The thinking in this was that pilots could become licensed for recreational flight much more quickly than for flight in heavier aircraft.  The basic requirements of Light Sport are:
Gross Weight < 1350 lbs.
Speed at Max Power < 120 knots
Altitude < 10,000 
Max People:  2
Retractable? No
Within these requirements, a very nice airplane can be defined.  Two full-size adults can fly in a modestly equipped airplane with a reasonable quantity of fuel.  A speed of 120 kts is about 130 mps - 2x the speed of a car.  And few VFR pilots get above 10,000 feet.  So, not really that restricted.   
Make no mistake about it.  Light Sport is flying a real airplane.  Learning in a light sport will make anyone a better pilot.  J3 Cubs, the main consumer plane of the late 40's and 50's is in the Light Sport category.  As are Luscombe's, Ercoupe's and Aeronca's.
Some say Light Sport never "made it" in aviation.  I find the opposite to be true.  Light Sport is the ideal way to learn to fly, because you have "FLY THE AIRPLANE."  I learned in Pipers, but in a Cherokee 140 (for example) you could be really lax on rudders and pitch.  Not so in Light Sport.  These airplanes are nimble and responsive.  Like comparing a motorcycle to a car.