Two cows are grazing in a field, and one says to the other, "Hey man, are you worried about this mad cow disease thing?" And the other one says "What do I care, I'm a helicopter? Bbbbbbbbbbbbbbbb" [you have to stick out your hands make a helicopter sound]

两头牛在操场吃草，一头对另外那头说，“这个疯牛病的事情，你害怕吗？” 然后另外那头牛说，“怕什么牛病啊，我是直升飞机呢! Bbbbbbbbbbbb...."

Chinese, Chinese, Chinese.

hi Rakifi:

what about this one? Is it the so-called black sense of humor?

就算是Believe，中间也藏了一个lie；就算是Friend，还是免不了会end；就算是Lover，还是可能会over；就算是Wife，心里也夹杂着if…… 让人欣慰的是： 就算是完全impossible，但还藏着个possible， 即便是Forget，也曾经get

I am afraid I might be bad at translating  but you probably can get it. It means there hides a "lie" in "believe". "Friend" will come to an end. "lover" will be "over", and the husband suspects "if" about his wife... But it also comforts people that there hides a "possible" in "impossible" and even if we have to "forget" some pains, it means we still have already "get" some happy time..

And this one:

Chinese: I'm sorry.

Foreigner: I'm sorry too!

Chinese: I'm sorry three.

Foreigner: What are you sorry for?!

Chinese: I'm sorry five!

  I've got 'em laughing with this one a few times:

    两个人是在一起工作的。 一个叫小王，另一个叫小猪。有一天小王对小猪说，“小猪，你能帮我个忙吗？我今天忙死了。肯定会晚点回家。你能去我的那里告诉我老婆我会晚点回家好不好？” 小猪说“当然可以啊！没问题！“几个小时后小猪下班了，马上回到小王的家悄悄门。王太太开门说”小猪你好。请进来喝茶“。小猪喝茶时候就看到王太太的长腿。他说”王太太，你的腿这么长也这么性感。如果你给我看你的腿我会给你一百块钱，好不好？“王太太想了几秒钟在说”好的”就给他看她的腿。然后小猪说”我看到你的内裤是粉红色，对不对？如果你给我看你的内裤，我会给你三百块钱，好不好？“王太太想了几分钟在说”好的，看一下” 在给他看她的内裤。然后小猪说“天啊，你这么漂亮，这么性感。如果你跟我一起做爱我会给你一千块钱，好不好？”王太太想了好几分钟在说“好的，过来“。

    几个小时后小王回家了。王太太在厨房里做着菜。小王说”老婆，小猪今晚来这里吗？“ 她说”来了“。小王说”他告诉你我会晚回家吗？“她说”告诉我了“。小王说”他给你我的工资吗？“

I don't know any of the Chinese, but...

What did the farmer say to the cow on the roof?

Get down.

What did the cow say back?

Moooo.