Thank you for your messages and advice.

I felt much better almost instantly after I wrote that post. I had to get that out of my system.
I feel less hurt right now. The party is tomorrow, and I will attend - unless the friend in charge will go absolutely crazy tonight (completely possible!).
I find this whole process chaotic. I've been planning all sorts of parties and occasions for years, but I've never been part of something like this, I can tell you that! The party is tomorrow, but the pal in charge keeps on changing plans. I have absolutely no idea if I'm supposed to go to the bride's appartment on my own or if one friend's boyfriend will drive us all there. I hate this kind of uncertainty at this point. When plan is made, it's made. I make mine waterproof (literally) and stick to it. I do know for sure that the party begins at noon and I'm supposed to wear black.
It's summer, it might rain. I actually got a panic text from the pal in charge 6.15am this morning because she had seen the weather forecasts and rain showers are predicted. I reminded her that I did point out at the very first meeting ages ago that rain IS a possibility; after all, this is Finland! That's why the Aquarium is on the list and picnic is not compulsory.
It was my job to book us movie tickets in advance (movie Bridesmaids opened here last month). So far they have decided to drop the movie twice, then added it yet again. I have not cancelled the tickets just yet; knowing them anything can happen between today and tomorrow.
I've got the feeling that this will be a long, long day...

Mel, I've tried to ask which friend was in charge of my Bachelorette party. I don't know the answer to that. Knowing my friends, it was the bride or the very same friend who is in charge now. So, technically, I could sat this one out.
Christy, I told my friends for years that if I will ever have a Bachelorette party, I'd like them to take me to a nice restaurant for dinner (I even told them my favorite one, which is a Italian restaurant chain - great food & atmosphere, lots of options for all & prices are inexpensive) and to a nice romantic comedy, so it would be an evening with friends, good conversation, good food and great laugh. I aguess I didn't make it easy enough...

Back in here, women used to have more low-key Bridal Showers, too, but these days they are spending more and more time and money to create Bachelorette Parties. I still think it's funny that the friend in charge complained for me for years about the Bachelorette Parties she had to attend with her other friends; about the time and money wasted on those occasions. Now she is doing the exactly same for this friend.

Carolyn, when I first read your advice, my instant response was: going will make me feel worse. I actually considered what would change if I didn't go and what would if I did. The conclusion: they would have to pay a bit more for dinner (we will share the cost of the bride's dinner and other costs), someone else will need to find 10 one euro coins for the dance game and there will be no Pre Marriage Test, so in my eyes, no harm done, not really.
Linda, for the past few years, one friend of mine has changed in a great deal. I know for a fact that friends matter to her less than her romantic status - she told me that herself and with those exact words. Her changed behavior and values have not gone unnoticed, and many of us have been worried about her. She's the friend in charge.
Lenny, I wrote here, because what I thought about it all left me feeling hurt and confused. Now I feel more at ease, and I can honestly say that it was due to these posts right here.

I will let you know how it all turn out...

Sanna