The ASK-21 is a German two seat training glider of moderate performance (34/1), and is also certified for aerobatics. It is the longest continuous production fiberglass trainer in the world. It is well known for it's very lovely flight characteristics and climb abilities in weak lift. The K-21 has easily stood the test of time in the training environment and constantly comes out first choice among flight schools and clubs everywhere.  It is also an excellent choice for recreational flying and sport competition.
The SZD-50 is a two place glider manufactured in Poland by PZL Bielsko and is of fiberglass construction of similar size and performance as the ASK-21.  It is designed for primary, intermediate and  aerobatic training.  It is well known for it's spin characteristics which make it an excellent choice for spin training.  It has dive brakes that protrude from both the upper and lower wing surfaces giving great control for recovery from unusual attitudes.  It is approved for inverted flight.  You will hear it affectionately called the "Owl"
The SZD-51, also manufactured by PZL Bielsko, is a single seat fiberglass sailplane designed for club and recreational use.  It is an excellent sailplane for the solo pilot and for developing cross country experience.  The controls are light and well coordinated and it can climb with the best of ships.  This is a wonderful ship for honing ones soaring skills.
The Piper PA-18/160 is a workhorse tow plane that can be seen on many glider fields around the world.  It is a derivative of the famous J-3 Cub that first appeared in the 30's.  Because of it's low weight to power ratio, high power and low flying speed characteristics it is a natural for glider towing.  Being a 'tail dragger' helps to keep the weight down but does add a requirement for special training and endorsement for operating.