The HOGD preceeded Thelema but it does have its links in Aleister Crowley.
HOGD practises a beautiful system of qabalisitic, elemental and enochian ritual and initation. Crowley led the order for a time in the early 1900s but it pretty much died out due to diagreements between members over the connection that its previous leader SGMathers had with the "secret chiefs" (beings overseeing and guiding humanity".
Because of his background in the GD there is a lot of its practises recommended as practises in Thelemic magick - see Liber ABA, many of its rituals come from the GD.
GD initiation also permeates the initiations of the AA today.
Crowley did however evolve some of the symbolism and design a number of rituals that follow a similar format to the GD rituals but that have been "Thelema-ised"
Eg The Star Ruby (a pentagram ritual evolving from the LRP) and The Star Sapphire (a hexagram ritual evolving from the GRH) and Liber V vel Reguli (a greater pentagram ritual likend to the SupremeRitual of the Pentagram from GD) some might argue they are evolutions, some might say they are something different entirely.
The GD "Opening by Waterotwers ritual" also features highly in Crowley's Liber Samekh
The general structure of Thelemic magick as laid out in Crowleys Magick and Theory in Practise is mainly GD, but he firmly put the GD to bed in his later years. One of his students Isreal Regardie sought to revivie the GD and wrote the book we all know of. Crowley never really forgave him for doing this, so this shows his attitude towards it.
I think he felt his new system far superseeded the GD seeing it as part of the Old Aeon.
I dont know if itsstill going much these days - I know they used to have a temple in London but I think they sold it off