On 2/20 Momoi will be appearing along with many other artists at the Nico Nico Taikaigi tour as a guest.
That would likely be DAI kaigi.
If the first two kanji characters were by themselves, it would be "taikai" and if the second two kanji characters were by themselves, it would be "kaigi." In this case, it's actually "kaigi" with prefix (dai).
Finding the main word can be tricky sometimes, but it's not the worst thing about Japanese.
Sometimes, it's all context dependent, like 大人気, which could be だい人気 (dai nin'ki) or 大人げ (otonage). What a language!
...says the guy who recently made a stupid mistake while commenting on somebody's Mixi journal. Thank you big B&W bear-like creature sama for correcting me.
And excuse me for posting something unrelated to Momoi nor about NicoNico.