I don't know if other locations are doing this, but Costa's Jinya has several special ramens right now.
I tried the chicken tan ramen (I think it was called, red broth w/ beaten egg) it was ok... regular chicken ramen is better.
Then I tried the "tokyo tonkotsu" - a tonkotsu ramen with bonito shavings...
WOW. That was the best ramen I've had in my life, hands down. Only thing I should mention is they were pretty skimpy on the chashu, I definitely recommend ordering it with extra,