For example, I have been building and flying what used to be known as "F5B" aircraft. Back when we were using NiCd batteries I had planes that used 27 cells to power very compact multi-horsepower motors in these gliders that often are not any larger than about 2.4 meters in span. Back then (I am talking '80's '90's) these planes could climb out of sight in 5 seconds. They are, aerodynamically speaking, highly efficient. After the climb the competition consisted in completing as many laps of a circuit as possible without power, gliding at high speed. Once done, you get to use the motor again, climb to altitude and thermal (in some cases they don't to this). Finally, there's a requirement for precision landing --the closest to land to the center of a target the more points you earn.
Aside from that, I am very much into what some call "full house gliders", this to mean having a full set of control surfaces: two ailerons, two flaps, sometimes two spoilers, rudder and elevator. These are not typically high speed monsters. These days you use electric motors for the climb. I still have a winch (which was the traditional climb-to-altitude method) but have not used it in decades. With a full house glider the objective is to find and exploit thermals and, if in competition, usually have a precision landing just as explained above. I have had the experience of successfully thermalling for over two hours laying on my back listening to music, landing only due to just being tired more so than anything else.
There are a lot of great options these days to get into the hobby. You don't have to have a full-house glider to experience thermalling like a bird. One can get started with modest kits that are pretty much ready to fly. The more technically minded will eventually want to learn how to build from scratch or seriously modify aircraft (or both). While I haven't done it in a while, I used to regularly make custom planes using a range of materials, from balsa wood for normal performance planes to designing molds to vacuum-bag fiberglass, kevlar or carbon fiber designs.
Here are a few examples of the above:
F5B (I have several planes that look and perform just like these). The motor is only used to climb.
https://www.youtube.com/watch?v=T0z9iy2SJA0
https://www.youtube.com/watch?v=59V9ICM75co
https://www.youtube.com/watch?v=d4J8VQ4iNwQ
https://www.youtube.com/watch?v=MNydX3aOTr8
This type of glider/event seems to be far more popular in the US: