How many vegetarians does ...

Q. How many vegetarians does it take to screw in a lightbulb?
A. I don't know, but where do you get your protein!?

http://www.vegetus.org/jokes/jokes.htm

What did one vegetarian spy...

Q. What did one vegetarian spy say to the other vegetarian spy?
A. We have to stop meating like this.

http://www.jokes-db.com/jokes/vegetarian-jokes

Why did the Tomato go..

Q. Why did the Tomato go out with a prune?
A. Because he couldn`t find a date!

http://www.jokes-db.com/jokes/vegetarian-jokes

What did the lettuce say...

Q. What did the lettuce say to the celery?
A. Are you stalking me?

http://www.jokes-db.com/jokes/vegetarian-jokes

Why did the tomato blush?

Q. Why did the tomato blush?
A. Because he saw the salad, dressing.