The rabbis say that in the time of the moshiach (messiah) Yom Kippur, the day of atonement, will be like Purim. (There's word-play there.) No moshiach yet, but something along those lines (in reverse) is coming up.
I'm part of a group that's doing a pilot evaluation of a new machzor (high-holy-day prayerbook). Tomorrow night we're sort-of having a Kol Nidrei service for the evening of Yom Kippur. Should be interesting! Years ago our morning minyan piloted the new siddur Mishkan T'filah
(over several weeks) and I found that process very engaging for me. I'm looking forward to seeing what the new machzor has in store for us.
(Well ok; I have an advance copy of just this part of it and I paged through it tonight. But going through it with a congregation is different.)