Akiba-Don Quijote is a discount store chain that carries everything from groceries and toys to electronics and high end fashion goods. The Akihabara branch is home to the girl pop group AKB48, who perform daily shows at their theater on the 8th floor of the store (3000 yen). There is also a branch of the @Home Cafe maid cafe on the 5th floor of the store.
Everyone will need to apply for tourist and/or transit visas for the Mongol Rally, and once you have chosen your route, you really should plan out your visa timeline. http://www.spunkygirlmonologues.com/mongol-rally-the-lowdown-on-tourist-visas/