I've only really participated in 2 (not counting the current one) and I liked both.
one, as meimei said, the valentines one with the dresses,the heart crackers the went I LOVE YOU and the heart cookies that I wasted with my lvl 27 mage xD
the other being the more recent Stones Throw event (run by moderators, not GMs, i think) in which I found Kira 2nd for one of the hide and seek rounds and won 25 suns
I want more events XP