Tamarillo! I have had one of these before, ages ago, probably in New Zealand, but I couldn't remember what it tasted like. Though I did remember that I liked it, which was the main thing. (Then again, I remember liking corned beef but I doubt I'll ever pick some up in the supermarket just to recap ;)).
I wasn't sure how to eat it. Do I just bite into it like an apple? Hmm. I eventually decided to just cut it in half and eat it like a kiwifruit.
Yuuuuuuuummmm. I just scopped out the inside bits with a teaspoon and ate it. You just sort of swallow it (lots of seeds) rather than chew. It's a lot like a passionfruit. It even tastes a bit like a passionfruit. The one I bought was still a little bitter, but I don't mind. It's part of the Solanacae family, ie, the same family as tomatoes so it does have a little bit of characteristic tartness.
First I started just eating the seeds then decided to just eat the whole lot. Not sure if the skin is edible but I think it is gathering from just the introduction on this website. If only I could afford more of them! I'd love to try it in muffins. Unfortunately they cost $1.94 each at the moment, and I'm pretty sure I can't justify buying a whole heap. Damn.