Ochuugen (or just 'Chuugen') is the Feast of the Hungry Ghosts, held on the 15th of July according to the old calendar. I won't say too much about it this time, since I was working at the restaurant tonight.
Once, a feast would be held for the night when the dead are released from the Underworld, especially for one's ancestors and friends who had no family. Leave out plenty of delicious foods, such as white rice, citrus fruits, savoury things, and some delicate sweets for their enjoyment, and be sure to leave empty seats for them to take their place on that night! If there is a special ritual you would hold for them, this is the night. Treat them as if they are still living and enjoy your memories of times past.
Today, it is a gift-giving holiday, one of two major ones throughout the year. The next one is Oseibo in December. Each have their own buying and wrapping rules.
There was a lady who came in tonight and sadly, she didn't find much she liked out of what she ordered. But she did have the habit of sticking her chopsticks (ohashi) straight up in her rice- a custom reserved for serving food to the dead. Of course, I mention this only as a passing point of interest, given the atmosphere and relatively traditional interior architecture.
From a mystical point of view, some ghosts do not feel like returning to the Underworld, where they are now to live. They like to linger near the living- they cannot let go of this world, or perhaps a person misses someone who is alive and cannot be 'reached' from the other side of the veil. A ghost can drain the life out of a living person; it is not malicious, merely a side-effect of their condition. Therefore, it may become necessary to have your house ritually cleansed after this holiday by some priest, just to be sure the spirit is escorted properly back to the realm of the Dead.