HAGS: Hogwarts Apparition Game Society: This was meant to be a sort of hide and seek game for students who have been licensed to apparate. It was founded by one of the less intelligent students, who forgot that apparition is blocked at Hogwarts.
SQUEALers: Student QUilt, Embroidery or Adornment League: A group of students who learn the Muggle needle arts. Typically these skills are practiced non-magically, but can also be done using enchanted tools.
The THE Club: Top Healing Embodied: An organization that prides itself on indentifying the best healers in the Wizarding world. Only top healers are allowed to join. (Some people find this organization rather elitist)
FIRE and ICE: Flying Incantations, Riding Elements, and In-air Cartwheel Exhibitions: A club to learn and practice stunt flying on brooms.