At the end of this summer, First House Mizonokuchi 100⁺a and 100⁺b held a joint BBQ. The two houses are about a one-minute walk apart, and around 35 residents from both came along.
We stocked up at Costco for the big group. It rained on the day, so the grill stayed outside while everyone ate and talked indoors. The living room was full of English, Japanese and other languages, and the laughter didn't stop. A few housemates had birthdays around then, so we added a surprise birthday celebration too.
Residents from the two houses got along right away, which is what we enjoy most about joint events.