Cha Cha Club is a tea ceremony school teaching the almost-500-year-old Urasenke tradition with a "lesson style updated for the Heisei period" (平成版お稽古スタイル). For example, their FAQ sez:

Q: Do I have to wear a kimono?

A: No, of course not. Western clothes and even jeans are okay. However, on more formal occasions, jeans and other casual clothing are frowned upon.

Q: I don't think I can handle all that kneeling...

A: You can relax into a more casual posture if you like. [...] But you'll be surprised at how quickly you get used to kneeling as you practise.

Q: Aren't there lots of strict rules and things?

A: There is a "flow", but you'll pick it up naturally as you practise.

Ex-Urasenke director and current Right Angle chair 説田弘 (SETSUDA Hiroshi?) explains:

Things that Japanese people have valued for centuries are today being gradually lost. To ensure that the "Japanese soul" (和の心) is passed on to the next generation as it must be, those of us entrusted with transmitting it must conceive of new ways of doing so, appropriate to the modern age [...]

The question of whether you can jettison certain inconvenient and old-fashioned parts of a tradition and still call it the same tradition is somewhat philosopher's axe-y; I have never formally studied any beverage ceremonies of any kind, so I won't get into it here. It is interesting that they have two kinds of trial lessons, one for people who just want to experience an hour of pouring, rotating and sipping, and one that is "a trifle strict?" and includes, for example, guidance in how to sit when accepting the cup.