Yes, that's supposed to be Melody and the narrator having sex.

aparently serge hid a cassete recorder under their bed then tickled jane birkin

Sebadoh - Prince-S and Powerbroker.

Butthole Surfers - Perry and Waiting for Jimmy to Kick! Very demented screams and laughs.

Tim Tiny - The Laughing Policeman.

I forgot this one

David Bowie-the Laughing Gnome

odb had a ton, not sure which song (think its got your money) but the line is "throwing moet bottles hahahahahaaah!
00i00 have a slightly scary one on kila kila kila

Another version:

http://www.youtube.com/watch?v=TTan_ZWGEUU

SY - Stereo Sanctity
Sleater-Kinney - Rollercoaster

but both of those are either at the end or beginning

one memorable one as nicfit said was Barbara Ann by the Beach Boys

Magma - Ork Alarm...evil laughing at the end .

'seven... SEVEN!... ha... durrrghhhhneeeerrrrrgggghhhhhh tsh tsh tsh tsh woooooooooooooooraooowwwnneeeeunnneeerrneeerr'

Pavement - Summer Babe
The Cribs - Be Safe (lee) 'hahaha, that's the spirit'

Green River - "Your Own Best Friend"
Pere Ubu - "Humour Me"

the two Bowie songs already mentioned were the first I thought of though.

Sonic Youth - No Part II

Oh wait... it's not exactly THAT

Black Flag - Nervous Breakdown

many afrirampo songs

"The laughing song" by that one band

the beginning of an idiot flesh song, I don't remember what one

has no one mentioned flipper yet? what the fuck. they have 'ha ha ha ha' as a chorus.

yes.

there's a brilliant laugh in "brain damage" (pink floyd)

bob dylan's 115th dream.

Black Sabbath "Am I Going Insane"

System of a Down "Devil"

o fuck, i missed gravity slip's post apparently, my bad.

nirvana - "milk it" (as already mentioned), "I hate myself and want to die", "Curmudgeon" (at the very beginning.

roky erikson - "burn the flames"

and nearly every damn suckdog "song".

Pavement's Wowee Zowee has giggles(strange ones at that) all over it, especially at the end of Brinx Job