For a few nights a week, the futuristic cruise-boat Himiko, designed by manga and anime artist Leiji Matsumoto, morphs into this floating bar. Board on the hour at Hinode pier and the half-hour at Odaiba Kaihin-k艒en. The evening-long 鈥榝loating pass鈥 usually includes some sort of live music; check the schedule online as sometimes events drive up the price.
Note that this won't run in the event of a typhoon or similarly inclement weather.