For some reason I can't be funny.

[IamDeath]

Even though I think i am really funny but when it comes to talking to other people (especially girls) i really lack my sense of humour. I get really nervous and usually dont say any thing funny infront of them. People think i am a really serious guy.

[DoesntMatter]

That's because girls are scary

[candle23]

^lollllllllll

[IamDeath]

^ and they smell funny

[Gribble]

Being funny is mostly about being confident. If you are confident you can say the most un-funny thing ever, but your inflection and facial expressions will have people sniggering. If you're nervous, however, you could be onto a comedic goldmine, but it don't mean a damn if your timing is off and your voice cracks mid-joke.

Chicks ain't scary. You just got to get used to them. Start chatting them up politely. Build up your comfort levels, then allow the funny to flow. Don't try too hard. A good joke just... rises up. It pops into your head in the heat of the moment and you let it loose. You don't reach for it yourself.

[Raze]

That's because girls are scary

LMAO! Yes, yes, they can be.

[Paro]

Okay, I agree that girls can be scary, just as scary as it is to talk to guys. But we do NOT smell funny! Typically women tend to exercise better hygiene than men, and we've got some ragingly awesome smelling shampoos.

With regard to your problem about not being funny in front of the opposite sex, people tend to crack the greatest jokes when they're among friends, because they feel comfortable around them. You're problem isn't difficulty executing the jokes, but just feeling comfortable around other people, especially girls. One way to feel more comfortable is to not care about other peoples' response to you. Make jokes to make yourself laugh, not other people (but don't laugh out loud at your own joke, because you may look like an a-hole, or just psychotic). Also, when I'm nervous around other people, I just tell myself that they're just as nervous as I am, because usually they are. Everyone's concerned about making a good impression and being liked.