wrote:

Does anyone still do this? It is illegal in the USA but does anyone do
it anywhere else? Be glad to have any info about articles/accounts of
people who have done this.

In Germany, too, AFAIK.

Also has anyone been able to climb up the sunny side of a cumulus
cloud? Read somewhere that one famous glider pilot did this and he
said it was the flight of his life.

I did this twice on different occasions. It isn't always the sunny side you
can climb, but the upwind one.
The first time was several years ago over a power plant with a special
cooling tower that provides great thermals. While circling around a kind of
cloud hose, another Cu showed up about 300 ft below me. Because of strong
wind that day, I flew to the upwind side of it and was able to climb a few
hundred feet above cloud level in front of the quickly building cloud.
It was very similar to ridge soaring but without fear of catching a tree or
rock.
Another time I found very different cloud base altitudes at the border of
two different masses of air. Flying from the higher cloud base in the
direction of the lower one against the wind, I found laminar lift without
seeing a cloud near me. At first, I thought I had found wave, but a Cu
built some minutes later directly below me.
I think, an important thing for trying this kind of gliding is strong wind
at the level of cloud base and strong thermals with a small diameter. The
climbing thermal then pushes a bumb into the airflow of the wind which can
be used like a ridge or wave.

I'm not a famous glider pilot but I hope to have helped.

Greetings from southern Germany, Erik.

TIA
George (ex-kestrel254)