The Holly Festival I went to while in Russia was amaaaaaaaazing. It was a giant empty field with probably couple hundred people all buying a chalky version of paint and then....
smacking it in each other's faces.
Although the practice sounds borderline barbaric, the environment of the place is as close to a con as I've found outside of a con, which, if you know me at all, is a huuuuge compliment. Everyone is there to have fun and you go up to strangers (and have them come up to you) with the familiarity level of friends. It's a pleasant change from the usual and I enjoyed it so much I ended up staying way longer than expected. Admittedly, it would have been funner to attend with friends than fam, but I regret nothing in attending it!
The music was interestingly enough, mostly in English, Jesus was it hot that day and...
oh yes.
They decides to uh....shower the crowd with a giant water hose to wash off the chalk paint. Lots of screaming ensued, but it was all in good fun.
And hey, they say the more chalk you're covered in, the more happiness they wish you for the upcoming year.
I'd say everyone got their fair share.