(repeat each line after song leader)
I said a Boom Chicka Boom
I said a Boom Chicka Boom
I said a Boom Chicka Rocka Chicka Rocka Chicka Boom
Uh huh
Oh yeah
One more time ______ style.
Janitor Style:
I said a Broom Sweep-a Broom
I said a Broom Sweep-a Broom
I said a Broom Sweep-a Mop-a Sweep-a Mop-a Sweep-a Broom
Valley Girl Style:
I said like boom chicka boom
I said a totally boom chicka boom
I said like boom chicka like rocka chicka like gag me with a spoon
Baseball Style:
I said a boom chicka boom
I said a boom chicka boom
I said a boom chicka rocka hit that softball to the moon.
Barn-yard Style:
I said a moo chicka moo
I said a moo chicka moo
I said a moo chicka watch your step, don't track it in the room.
Race Car Style:
I said a vroom shifta vroom
I said a vroom shifta vroom
I said a vroom shifta grind-a shifta grind-a shifta vroom
Astronaut Style:
I said a moon shoot the moon
I said a moon shoot the moon
I said a moon blast-me shoot-me blast-me shoot-me-to-the-moon
Flower Style:
I said a bloom chicka bloom
I said a bloom chicka bloom
I said a bloom chicka blossom smell those flowers chicka bloom
Parent Style:
I said a boom GO TO YOUR ROOM
I said a boom GO TO YOUR ROOM
I said a boom GO TO YOUR ROOM and don't come out 'til next June.
Cheerleader Style:
I said a Boom-Go-Fight-Boom
I said a Boom-Go-Fight-Boom
I said a Boom Go-Fight-Win Go-Fight-Win Go-Fight-Boom
Taco Bell Style:
I said a bean chicka bean
I said a bean chicka bean
I said a bean and cheese burrito and a nacho supreme.
Arnold Schwarznegger Style: (Dana Q. Pack 75 in Long Beach)
[speak it slowly with a heavy 'Ahnold' accent and shoot a gun on every BOOM]
Ich spracht Boom Chicka Boom
Ich spracht Boom Chicka Boom
Ich spracht Boom Chicka Rocka Chicka Rocka Chicka Boom
Ah hah
Oh ja
Noch ein mal ______ style.
McDonalds Style:
I said a Big Mac and Fries
I said a Big Mac and Fries
I said a Big Mac and Fries and dont forget to Super Size.
Photographer Style:
I said a zoom clicka zoom.
I said a zoom clicka zoom.
I said a zoom clicka Smile Watch the Birdie clicka zoom.
End of the World Style:
I said a Doom Chicka Doom.
I said a Doom Chicka Doom.
I said a Doom Chicka *Huge Explosion Noise* Chicka *Huge Explosion Noise* Chicka Doom.
Homie Style:
I said a grill shiny grill
I said a bling chicka bling
I said a Honda Civic rims a-spinnin' on my Limousine
Fonzie Style:
I said a vroom chicka vroom
I said a vroom chicka vroom
I said a vroom chicka aaaaaaye chicka aaaaaaye chicka vroom
Thunderstorm Style:
I said a boom crasha boom
I said a boom crasha boom
I said a boom crasha flasha crasha flasha crasha boom
Space Style:
I said a space chicka space
I said a space chicka space
I said there's a Pluto there's a Mars there's the Earth and there's the stars
Surfer Style:
I said a dude chicka dude
I said a dude chicka dude
I said a dude chicka wipe out chicka WHOA chicka dude
Conservation Style:
I said a tree hug a tree
I said a tree hug a tree
I said save the whales, save the gas, save the water, hug a tree
Librarian Style:
I said a book read a book
I said a book read a book
I said a book choose a novel, keep it quiet, read a book
Bee Style:
I said a Bzzzz chicka Bzzzz
I said a Bzzzz chicka Bzzzz
I said a Bzzzz flower nectar pollen honey chicka Bzzzz
Fire Style:
I said a OUCH chicka OUCH
I said a OUCH chicka OUCH
I said a OUCH burnt my finger in the fire Chicka OUCH
Speeder Style:
I said a Vroom Squeela Vroom
I said a Vroom Squeela Vroom
I said a Vroom Theres a Coppa Betta Stoppa Chicka Vroom
Cellphone Style:
I said a call me on my cell
I said a call me on my cell
I said a call me, text me, call me, text me, call me on my cell
Star Wars Style:
I said a zoom chicka zoom
I said a zoom chicka zoom
I said a Luke I am your father Join the Dark Side chicka zoom.

There are other Styles to say the normal lyrics rather than making up other words:
Baby style
Grandpa style - with lips wrapped over teeth
Frankenstein style
Opera Singer
Underwater - wiggle finger over lips