May have been mentioned elsewhere, but a summary of pros & cons of taking up gliding:-
Pros - Great fun, very "team-spirited", great way to do lots of cheap flying, definately makes you a better pilot, lots of variety compared to GA flying.
Cons - Very time consuming (not family-friendly if you have young kids), even more Wx-dependant than VFR GA (perfectly good flying Wx can be crap Wx for gliding), some odd characters around & politics/arguments in clubs, can be cliquey.
I did it for a while as something different to do, enjoyed it and it made me a much better pilot, but in the end it wasn't compatible with family life and I came across a few weirdos (including one downright nasty bugger) which I became wary of. Went back to powered flying with a very different perspective. If you have the time, I'd do it.