[QUOTE=Autolycus]
Here’s a funny Japanese linguistic pun:
僕はうなぎです。 Boku ha, unagi desu. By itself, this means “I am an eel,” but in context it almost certainly means “I will order the eel,” like in a restaurant. Tee hee 
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Funny being a relative term here. Puns are funny / stupid depending on their simplicity vs. the linguistic level of the recipient. Most kindergarten children and beginning speakers of Japanese will be amused. It would certainly be disappointing to expect adults to find puns on this level to be highly amusing.
One pun I learned when I was first over here to asking children “kaeru no?” “Are you going home?” and “Are you a frog?.”
[QUOTE=Frylock]
I made one up which I swear is grammatically correct to my knowledge, but nevertheless no Japanese person could understand it. I must have something wrong:
Ankara kara dakara, karai. (It’s supposed to mean ‘Since its from Ankara, it’s espicy.’)
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While “kara dakara” is not grammatically incorrect per se, this sentence would not normally be used by a native.
Your problem is with “kara,” which typically takes a more literal meaning in Japanese and does not always have an implied meaning of “and thus shares similar properties of others from the same place.” At the risk of perpetrating stereotypes, the following could be easily followed in English but a literal translation into Japanese would not work.
A. Damn, your friend drinks a lot of beer.
B. Of course, he’s from Australia.
In Japanese you would more typically say “becasue he’s an Australian.” “オーストリア人だから”
から・だから can be used as “since; because; owing”
東大出だからといって有能だとは限らない. A man is not necessarily competent simply because he graduated from Tokyo University.
Note that this would not be東大から、だから.
Our friendly punster did enjoy your joke, but agreed that it didn’t work.
However, he suggested an alternative, which would take some work to get into a punch line.
アンカラからだから、空だ。It empty because it (a package or box, etc.) is from Ankara. You would need to find a joke which sets this up, maybe along the lines that Turkish Postal workers regularly steal everything. I can’t imagine this would make you popular in the Mideast, but you can’t have your pun and eat it too.