Okonomiyaki is a combination of okonomi which is "what you want" and yaki which is "grilled or cooked". The servers bring you the ingredients and you cook it yourself based on your preference. There are a variety of ways to build your okonomiyaki and it is sometimes refer to as a "Japanese pizza" by Americans. There are two styles of okonomiyaki: Hiroshima-style and Kansai-style. Hiroshima-style okonomiyaki is layered like a giant omelette and often includes yakisoba on the inside, with a fried egg on top. Kansai-style okonomiyaki on the other hand is mixed together before being cooked like a pancake. The signature white sauce on top is Japanese mayonnaise which seems to be very popular.
Yakisoba is a wonderful dish that has been heavily integrated into the Japanese food culture much like ramen. Soba refers to to Japanese noodles made from buckwheat however, now the noodles used are similar to ramen noodles and are made from wheat flour. Yakisoba is stir-fried with pork, vegetables, and flavored yakisoba sauce.