• Acapella songs: "Memories", "Carolina", "Ragtime Gal (Hello My Baby)", "Amazing Grace" (though 5-8-93 and 10-20-95, for instance, were not acapella), and "The Star Spangled Banner" (both at Phish shows and at various sports events, including the Sunday 2pm Philadelphia Flyers game 5/5/97). Also, "Wolfman's Brother" between "You Enjoy Myself" and "Wolfman's Brother" at (4/26/96 I), and the "YEM" intro on the White Album. The band even took barbershop quartet lessons.
• Costumes: Mike often wears a lime-green jump suit. (Actually, Fishman has wore a lime-green shirt, e.g. playing with Pork Tornado on 1/26/97.
  
• Special dances by Trey and Mike in "Guelah Papyrus", "Landlady" (and therefore also in PYITE), "It's Ice", "Cavern", "Manteca", and, of course, "Moma Dance". Plus, new as of Summer 1999, the Meatstick Dance.
• Dry Ice: Phish started pumping insane amounts of dry ice in 1987, particularly at shows at the Living Room. See lights for discussion of effects.
• Bubble Machine: Only once so far: 10/31/94.
• Glider things: blue mats and slick socks, so the user can slide back and forth as though skating, used in 1993 "Glide"s and "It's Ice". Reportedly ordered from a latenight TV commercial seen by Trey and Fish in a hotel room while on tour.
• Odd instrumentation, in particular Henrietta's Vacuum cleaner
• Beach Balls: The Bill Ball Jam (1st time played was 11-19-92 Ross Arena - St. Michael's College, Colchester, VT ) where giant balls were pushed into audience, each ball named Trey, Page, Mike, and Fishman. When a ball was touched the audience the respective band member would play, creating a spontaneous free form jam and the balls bounced around the room. I only got to see this once in 1994 at the Bob Carpenter Center, Deleware. They did the Big Ball Jam extensively in '93, '94. Havent done one in awhile. (Thanks to Jason Espie <jespie@mountain.org> 7/15/99)
• Musical costumes: Mostly at HalloweenShows ' ;return true">Halloween shows, Phish has imitated the Beatles, The Who, Talking Heads, Velvet Underground, and Pink Floyd by playing a seminal album by each, in its entirety.
• Rotation Jams: where the band swaps instruments while jamming. They did this at the following shows 12-29-96 Spectrum, Philadelphia, PA; and 02-13-97 Shepherds Bush Empire, London, England. The rotation does not lend itself to quality jamming (this is one where antics disctract from the music some), but is a novelty and is testimony to the multi-talented nature of the group.(Thanks to Jason Espie <jespie@mountain.org> 7/15/99.) See also instruments - rotation and jamming types - rotation.
• Nakedness: If you're lucky (?), you might see Henrietta get naked. He did it first in April of 1989, lowered from the rafters at the Front trying to play an unamplified vacuum, and did it more recently during "Revolution #9" at the Halloween show 10/31/94. (The entire band stripped for a Feb. 1997 Rolling Stone issue.)
  
• Phone: During the fall and NYE 1997 tours, there was a mug, then a phone, then a rubber chicken, and then a plastic cup on Page's piano. For summer 1998, it was a white phone. Each is believed to have concealed a microphone with which Trey communicated to an earpiece Page wore. (Thanks also to Steve Cunningham <dblbogey@udel.edu>
• Trampolines: Syncrhonized (though some changes, eg Trey might spin 270 degrees left instead of 90 degress right to face Page).
• Silent jams: Phish continues "jamming" without actually creating sound, as in the YEM at 12/9/95.
• Stage banter: Things they've said during or between tunes are often interesting for their arbitrariness, but also because it sometimes stretches across several shows. For instance, the worm banter at 7-1-97 or the "Prison Joke" at 4-11-91.

See also:

"Impose rules to make life simpler. Break them to make life more fun."
-- Jon Fishman

If you're going to watch bands stare at their boots, you might as well come to our shows. Our boots are more interesting."
-- Paul Stanley of KISS