Looks like an Avocado. Not a the Hass variety. Rather, the Mexican type.
Let me know if you find out. Take care...
Barry
San Francisco, Ca
s/v Mobuki
Website-www.mobuki.tumblr.com
e-mail-
ucg@ix.netcom.com

http://en.wikipedia.org/wiki/Crescentia_cujete

That link suggests calabash, but these fruits were not round like a calabash and the leaves are different too so maybe it's a sort of avocado then..?

Is it on a tree or a vine ? Because it could be a banana passion fruit (Passiflora mollissima) if it is on a vine.
http://fr.wikipedia.org/wiki/Passiflora_tripartita_var._mollissima

The leaves coming out in little clumps from the branch and the shape of the branch make me think calabash. The shape can be round or oval.

Yeah, that's definitely cujete or calabazo as it's called in Pananma. Has some medicinal properties but if I remember correctly it smells bad (I have dug out the fruit to make bowls or totumas)
cheers,
Frank

I was going to guess avocado. Did you eat it?