Kabbalah is an esoteric discipline in Jewish mysticism, containing a set of teachings explaining the relationship between God and the universe. It dates to around the 12th century and originated in Spain and southern France. There are different traditions and streams of thought within it, that might focus on theosophy, meditative practices, or (more controversially) white magic. It has been a strong influence on Jewish philosophy and mysticism.
Since the 1960s, universalist schools have opened up which teach Kabbalah to people of all faiths and ways of life, one of the contributors to New Age spirituality. You can also sign up for six week courses in introductory Kabbalah, making it very accessible. Possibly such courses are held in Stars Hollow, although it is slightly surprising Luke knows about them and approves, as he doesn’t seem the most mystical person. The show did seem to just give random Jewishness to characters whenever it felt like it.
Freeway (a mistake for highway????) beautification projects
Community groups often sponsor a section of highway in the US in order to maintain it, and provide volunteers to work on it. Such projects might include planting trees, shrubs and ground cover plants, mowing grass, weeding, mulching, and removing roadside litter. It seems like something Taylor would almost certainly organise for a highway near Stars Hollow.
Color Me Mine pottery painting
A chain of studios, founded in 1996, where people can paint their own pottery and ceramics. In real life, there aren’t any Color Me Mine studios in Connecticut (but plenty in California, where the writers live).
Humorously, Luke’s suggestions of social activities he might approve don’t sound like anything most teenage boys would be interested in.