What IS it!?!

Can anyone tell me what this fruit is and how you are supposed to eat it? I am at a loss. DH picked it up at the store a couple of weeks ago and I cut into it and tried a bit and it was NOT good. I am unsure if that was it's natural taste or if it wasn't ripe or what. I really was wondering what they would be selling it at the grocery store for if that is all there was to it. Maybe it is a delicacy in some countries?

Any ideas!?!

UPDATE:

Jobina went to http://www.thefruitpages.com/guavas.shtml and found out it is a Kiwano. This is what this website had to say:

Kiwano
The horned melon.
Is a member of the cucumber family and not of the kiwi family. (which is funny, because DH and I thought it tastes a little like cucumber seeds when a cucumber isn't really good.)
Looks like an oval melon with horns and is very decorative.
Picked green, riped orange, the kiwano tastes like a mix of lemon and banana.
It is a tropical fruit so it cannot be stored in the refrigerator.

It has a link to recipes after that, but not any specific to the kiwano fruit. I did do a search after reading Jobina's comment and finding out what it was, and found this link with a beautiful picture the author took and some great recipes, which actually made me wan to go out and but a new kiwano so I could try them. :)