Slang is constantly changing and it is hard to keep up with.
Here are some of the slang that was used in the 90's. If you want to sound a little old school then you might want to learn some of these.

* Ai'ight - a unique way of saying "alright" or "okay".
Example - Ai'ight, I will meet you at your house at 9.

* All that an a bag of chips - a way of saying that the person is the best, and even better than that.
Example - Lauren has such an ego, she really thinks she is all that and a bag of chips.

* It's all good - don't worry, everything is okay.
Example - I know you owe me twenty dollars, but it's all good, you don't have to pay me back.

* Lay off - Stop it.
Example - Would you just lay off and stop yelling at her?

* Straight Edge - refers to a person who is very good and doesn't smoke or drink or do drugs.
Example: Man! Charles is such a straight edge! He won't even come and party with us!