Don’t be original all the time. Movies, textbook accompanying CDs, the radio . . . Sure, it’s all scripted, but you are not yet in a stage of life where you can get hit for verbal plagiarism in your everyday speech. So go for it! Borrow from the professionals!
Movies, movies, movies. Listen in Spanish and read the English subtitles. When you see something you like, write it down and listen to it over and over again. Repeat it with the same tone, speed, and intonation as the actor. Then bring it to class and drop it in a dialogue.
If in class you hear a phrase that strikes you and your friends as funny, get everyone to use it. Make it a game. Who can use it correctly most often? Quote it until someone makes you stop.
Randomly throw Spanish into your English conversations. Use the words that sound funny.
Speak English with a Spanish accent. This will improve your accent and the accents of those listening to you.
Give your best friends Spanish nicknames. In much of Spanish speaking culture it is culturally acceptable to call good friends names like “shorty,” “big nose,” and “skinny.” Don’t be cruel. Be able to take whatever you dish out.