The best of the best is lucky board. You will get a lot of magatamas, seal/summon scrolls, refine runes, money, and lucky ninja packs which can give superb lvl 4-5 magatamas, ninja frags, refine runes etc and on top of that you get points with each roll of the dice, which you c*e to buy things in the event's shop. Usually 2 ninjas, and some handy items, last time it was danzo, OP Hidan, medium threads/refines. So if you have the patience, stack your coupons and go crazy on the lucky board.